290 



Hagen: Hymenoptera 



. . . VESPOIDEA, POMPILIDAE, Anoplius Dufour 1834 



— Wing venation more or less reduced; hind wing nearly 

 veinless and with no closed cells; minute species 



PROCTOTRUPOIDEA ... 4 



4. Antennae inserted close to clypeus 



SCELIONIDAE, Tiphodytes Bradley 1902 



— Antennae inserted on middle of face 



DIAPRIEDAE, Trichopria Ashmead 1893 



5. Fore wing with 2 recurrent nervures; 1st cubital and 

 1st discoidal cells not separated; all the abdominal 

 segments freely movable . . . . ICHNEUMONIDAE ... 6 



— Fore wing with only 1 or without any recurrent nervure; 

 usually with the 2nd and 3rd abdominal segments 

 immovably united above BRACONIDAE ... 7 



6. Abdomen more or less compressed; areolet (= a small 

 cell near the center of the wing) more or less triangu- 

 lar or absent 



Ophioninae . . Cremastus Gravenhorst 1829 



— Abdomen depressed or cylindrical; areolet more or 

 less pentagonal, quadrangular, or occasionally absent 

 Cryptinae .. Apsilops Forster 1868 



7. Mandibles attached normally, their tips opposed and 

 meeting when closed; clypeus emarginate anteriorly, 

 forming with the mandibles a semicircular opening; 

 head posteriorly margined 



Rhogadinae, Ademon Haliday 1833 



— Mandibles widely separated, not meeting when closed, 

 the tips concave, the teeth curving outward instead 

 of inward Dacnusinae ... 8 



8. Eyes bare Dacnusa Haliday 1833 



— Eyes hairy 9 



9. Stigma short, wide; fore wing with Rs+M and M absent, 



1st cubital and 1st discoidal cells confluent 



Chorebidella Riegel 1950 



— Stigma long; fore wing with vein Rs+M and M present 

 or obsolescent, 1st cubital and 1st discoidal cells 

 separated 



. . Chorebus Haliday 1833 and Chorebidea Viereck 1914 



10. Tarsi 4- or 5-segmented MYMARIDAE .... 11 



— Tarsi 3-segmented .... TRICHOGRAMMATIDAE . . . . 13 



11. Phragma plainly projecting into abdomen; abdomen 

 sessile Anagrus Haliday 1833 



— Phragma never projecting beyond petiole; abdomen 

 petiolate or subpetiolate 12 



12. Abdomen distinctly petiolate; female antennae 9- 

 segmented C araphractus Haliday 1846 



— Abdomen subpetiolate; female antennae 10-segmented 

 Patasson Walker 1846 



13. Antennal club solid; marginal vein curved 



Trie ho gramma Westwood 1833 



— Antennal club segmented; marginal vein straight. ... 14 



14. Antennae 7-segmented (1 funicle segment) 



Prestwichia Lubbock 1863 



— Antennae 8-segmented (2 funicle segments) 



Hydrophylita Ghesquiere 1946 



Family POMPILIDAE 



The only pompilid known to be aquatic is Anoplius 

 (Anoplius) depressipes Banks 1919. It is a medium- 

 sized, entirely black spider wasp occurring throughout 

 the Alleghanian fauna of northeastern and north 

 central United States. Evans (1949) found that this 

 species had been misidentified in the literature under 

 such names as Priocnemis flavicornis, now known as 

 Priocnemoides fulvicornis (Cresson) 1867, and as 

 Anoplius illinoiensis (Robt.) 1901. The prey of A. 

 depressipes, according to Evans, consists of pisaurid 

 spiders belonging to the genus Dolomedes. 



Needham and Lloyd (1916) described how A. depres- 

 sipes, under the name of Priocnemis flavicornis, drags 

 its spider prey over water. The female is unable to 

 carry such a heavy burden in sustained flight, but 



the buoyancy of the spider body permits the wasp to 

 skim along the water surface with it (Rau, 1934). 

 Evans (1949) calls attention to an interesting paper 

 by Caudell (1922) which had been overlooked by 

 authors dealing with aquatic Hymenoptera. Caudell 

 describes the adult aquatic habits of A. depressipes 

 under the name A. illinoiensis. This species crawls 

 beneath a floating leaf or down an edge of a stone 

 when entering the water and has been observed run- 

 ning across the bottom of a stagnant pool. 



Superfamily PROCTOTRUPOIDEA 



In the superfamily Proctotrupoidea, only two species 

 are recorded as exhibiting aquatic habits, Tiphodytes 

 gerriphagus (Marchal) 1900 of the family Scelionidae 

 and Trichopria columbiana (Ashmead) 1893, a diapriid. 



Family SCELIONIDAE 



Marchal (1900) described Tiphodytes gerriphagus 

 under the generic name Limnodytes. In 1902, Bradley 

 proposed the new name Tiphodytes for Limnodytes 

 which was preoccupied. Marchal found the insect 

 through his embryological studies of Gerridae. He 

 was made aware of the parasite's presence by the 

 undulating movements of larvae which he could see 

 through the chorion of the gerrid egg. This species 

 is found in Europe and eastern United States, and is 

 a parasite of Gerris eggs, reaching them readily by 

 swimming with both the wings and the legs (Matheson 

 and Crosby, 1912). However, Martin (1928) observed: 

 "The adults flying about lily pads or walking over 

 them. After the female landed on a leaf she usually 

 walked straight to the edge of it. When a suitable 

 place was found, she first dipped her head under the 

 surface film of the water and after a few struggles 

 with it, succeeded in pulling herself entirely under 

 water. Clinging to the underside of the pad, she 

 walked about searching for gerrid eggs." Martin 

 observed a second manner of oviposition. Instead of 

 going head first, the female backed into the water 

 and clung to the lily pad with the front pair of legs, 

 while the middle pair hung in the water and the wings 

 as well as the hind legs floated on the surface film 

 of the water. In this position the female was able to 

 parasitize the gerrid eggs. Trepobates eggs were also 

 found to be parasitized, and a single parasite emerged 

 from each egg. 



The first instar larva of T. gerriphagus is "telea- 

 form." It is characterized by a complete lack of 

 segmentation but has the body divided by a sharp 

 constriction into two more or less equal parts. Clausen 

 (1940) draws attention to Marchal's (1900) illustration 

 of a T. gerriphagus larva showing distinct tufts upon 

 the summits of a pair of fleshy lobes situated at the 

 lateroventral margins of the anterior part of the ab- 

 domen. Martin (1928), dealing with same species, 

 shows the hairs in a transverse row. Perhaps our 

 North American Tiphodytes is an undescribed species 

 though the adults resemble each other. 



