New record of Brachycyrtus Kriechbaumer, 1880 (Hymenoptera: Ichneumonidae) from Venezuela and notes about their association with some chrysopid species

Brachycyrtus pretiosus Cushman, 1936 is recorded from Venezuela for the first time. The green-lacewings species Ceraeochrysa valida (Banks, 1851) and Ceraeochrysa fairchildi (Banks, 1946) are considered as the first known recorded hosts of Brachycyrtus cosmetus (Walkley, 1956). Illustrations of the studied Brachycyrtus spp.. Adults, final larval instar cephalic structures of B. cosmetus and maps with geographical distribution are provided.

Brachycyrtus species are considered solitary ectoparasitoids of the cocooned prepupae and pupae of Chrysopidae (Neuroptera) (Gauld & Ward 2000). The larva presents features characteristic of this lifestyle, the mandibles with dorsal blade margin denticulated, labral sclerite present, and spiracular closing apparatus separated from the atrium by a section of trachea (Wahl & Gauld 2002). However, Wahl & Gauld commented that they were unable to observe the antennae and the determination of its condition is necessary.
The Venezuelan Brachycyrtinae fauna is practically unknown and only three species: Brachycyrtus cosmetus (Walkley, 1956) The samplings were carried out sporadically in a citrus orchard in the "Estación experimental Miguel Luna Lugo" Universidad Centroccidental Lisandro Alvarado, Lara state, Venezuela (10° 01' N -69° 16' W, 520 m) during the period of July 2007 to July 2011.
Cocoons of chrysopids were collected manually and placed in separate voile-stoppered vials until the emergence of chrysopids or parasitoids. The specimens of Brachycyrtus spp. obtained were pinned with corresponding parasitized chrysopids cocoons and posteriorly analyzed; the adults chrysopids were pinned and identified. Both, the parasitoids and chrysopids, were deposited in the Museo Entomológico "José Manuel Osorio" (MJMO), Universidad Centroccidental "Lisandro Alvarado".
To obtain the cephalic capsule of the parasitoid, the internal debris of the parasitized chrysopids cocoon was carefully removed and macerated in KOH 10% for 45 minutes, washed with distilled water, pigmented with Clorazol Black E®, mounted on the slides and photographed under the microscope. The hymenopteran larvae nomenclatures followed Howar (1987) and Bennett et al. (2019). The identification of the Brachycyrtus species were carried out according to Gauld & Ward (2000), and the species of parasitized chrysopids were identified by comparing the cephalic capsules of exuviate with previously obtained chrysopids species from larvae, or by comparing with the illustrations in Tauber & De Leon (2001).
The photographs of adult parasitoids were obtained with a digital camera attached to a stereomicroscope Leica M205C APO and figures were prepared using Adobe Photoshop software (version 11.0). The distribution map was made using SimpleMappr online software (Shorthouse 2010).
Here, a total of 134 adults of Chrysopidae were obtained and grouped in the genera Leucochrysa McLachlan, 1868, Ceraeochrysa Adams, 1982and Plesiochrysa Adams, 1982, and also eight parasitoids specimens were obtained, of which six were Brachycyrtus cosmetus and two were B. pretiosus.
Adults of B. cosmetus ( Figure 1A-B) were obtained from cocooned pupae of both Ceraeochrysa fairchildi (Banks, 1946) and Ceraeochrysa valida (Banks, 1895), these being the first host records known to the parasitoid.
The cephalic capsule of the third instar larva of B. cosmetus was found, mounted on a slide and photographed, and all their structures were duly labeled ( Figure 2) and compared with Wahl (1993). Similarly, with Wahl's evidence, the antenna was not observed, being the essential structure to help elucidate if the species is ecto-or endoparasitoid. However, another Brachycyrtus specimen from Amazon Basin exhibits disc-shaped antenna localized in the upper region of the cephalic capsule, which was observed by Sosa-Duque (unpublished personal observations). This fact will require profound studies, due analysis and comparison of the cephalic structures that are very important to help in the determination of parasitoids after the emergence of adults, as well as to define the parasitoid behavior.  We recommended future studies aimed for knowing the Brachycyrtus behavior, opening of some chrysopid cocoons and make external observations and internal dissection of the host to be able to note the presence of the parasitoid. We are aware that this process will lead to the death of the parasitoid, but it could be useful to obtain the larva in the host, and finally observe the cephalic structures attached to the larva in order to observe the presence of antennal disc, which can be lost during the molting process, or slide preparation, because of which the structure has never been documented. (Walkley, 1956)  New record locality. Venezuela, Lara state. Current known distribution. Argentina, Brazil, Costa Rica, Ecuador, Mexico, Peru and USA (Walkley 1956;Gauld & Ward 2000;Onody et al. 2009;Yu et al. 2016;Fernandes et al. 2020a;Fernandes et al. 2020b).