Family DIAPRIIDAE 



The other aquatic proctotrupoid species is Trichopria 

 columbiana (Ashmead) 1893, recorded in Virginia and 

 Michigan. Berg (1949), who studied the relation of 

 insects to plants of the genus Po tamo ge ton, roared 

 T. columbiana from four species of ephydrid flies 

 belonging to the genus Hydrellia in Michigan. Berg 

 implies that they are good swimmers. From the few 

 known life histories of Trichopria, it is suspected 

 that T. columbiana is perhaps a gregarious internal 

 parasite of Hydrellia puparia and thus would oviposit 

 into the puparium. 



Superfamily ICHNEUMONOIDEA 



The aquatic species of Ichneumonoidea are relatively 

 larger than any of the aquatic Chalcidoidea or Procto- 

 trupoidea. This is not surprising since all the aquatic 

 species of Ichneumonoidea parasitize either lepi- 

 dopterous or dipterous larvae, whereas the species 

 of the other two superfamilies except Trichopria, 

 attack eggs of various aquatic species. 



291 



Hagen: Hymenoptera 



Pseuderipternus is very long and slendor so as to be 

 nearly cylindrical. 



Fomily BRACONIDAE 



Like the Ichnoumonidao, most of the aquatic braconids 

 have been referred to as undescribod species. Since 

 Chore bus aquaticus Muesebeck 1950 was reared from 

 Hydrellia griseola var. scapularis Loew (Muesebeck, 

 1950), it is quite possible that tho adult enters the 

 water to parasitize the aquatic ephydrid fly. The 

 closely allied genera Chorebidea, Chorebidella, and 

 Dacnusa contain several undescribed species which 

 likewise are parasites of various species of Hydrellia 

 attacking Potamogeton in Michigan (Berg, 1949). The 

 type locality of C. aquaticus is Sacramento, Cali- 

 fornia. Riegel (1950) described Chorebidella bergi 

 from specimens which Berg reared from Hydrellia 

 cruralis Cresson on Potamogeton amplifolius Tuckerm. 

 in Michigan. The species Ademon niger (Ashmead) 

 1895 is another parasite of various species of Hydrel- 

 lia (Berg, 1949), and is evidently found from Utah to 

 the eastern coast of the United States. 



Family ICHNEUMONIDAE 



The majority of the aquatic species of Ichneumoni- 

 dae are referred to as undescribed species of several 

 different genera. Chagnon (1922) reported an ichneu- 

 monid which he observed crawling down a rush beneath 

 the water, and Cushman (1933) discussed aquatic 

 ichneumonids and the probable species of Chagnon's 

 observation, deciding upon N eo stricklandia sericata 

 Viereck 1925, a species now placed in the genus 

 Apsilops (Muesebeck, 1950). Frohne (1939) observed 

 this species and four additional undescribed ichneu- 

 monids of similar habits in lakes of northern Michigan. 

 He concluded that A. sericata parasitizes the larvae 

 of Occidentalia comptulatalis (Hulst) 1886 and Chilo 

 forbesellus Fernald 1896. It was observed by Frohne, 

 ovipositing into the galleries of these pyralids in 

 Scirpus occidentalis (Watson). Another species of the 

 genus Apsilops, under the generic name Trichocryptus, 

 was recorded as a possible parasite of Schoenobius 

 melinellus disperellus Robison 1870 which bores in 

 spike rush (Frohne, 1939). Berg (1949) reared a 

 Cremastus species from Nymphula icciusalis Walker 

 1859, a pyralid which attacks Potamogeton natans 

 Linn, in Michigan. Frohne (1939) bred C. chilonis 

 Cushman 1935 from numerous cocoons found in the 

 larval galleries of two pyralids, C. forbesellus and 

 0. comptulatalis. Dr. W. H. Lange recently reared a 

 parasite from an aquatic pyralid, Parargyractis sp. 

 close to truckeealis (Dyar), which occurs near Colusa, 

 California. The parasite was determined by Miss L. M. 

 Walkley of the United States National Museum as a 

 new genus and species belonging to the tribe Cre- 

 mastini, and is near the genus P seuderipternus 

 Viereck (1917). The genus Cremastus is characterized 

 by having the thorax much stouter in front, or short 

 and thick, not subcylindrical whereas the thorax of 



Superfamily CHALCIDOIDEA 

 Family MYMARIDAE 



There are three aquatic mymarids known to occur in 

 the Nearctic region. Caraphractus cinctus Walker 

 1846 (fig. 1) (=Polynema natans Lubbock 1863) is 

 found in eastern United States, and parasitizes the 

 eggs of Notonecta, Dytiscus, and Calopteryx virgo. 

 Four to five larvae were found in each Notonecta egg. 

 This species swims with its wings, and has been 

 recorded to have lived submerged in water for twelve 

 hours (Matheson and Crosby, 1912). An Anagrus sp., 

 near the European A. subfuscus Forster 1847, is re- 

 corded as parasitizing gyrinid eggs in Kansas (Hoff- 

 mann, 1932) and also was taken from the stomach of a 

 trout in New York. The European species, A. brocheri 

 Schultz is unable to swim but moves about in the 

 water by walking upon foliage, plant stems, or other 

 objects (Clausen, 1940). 



Patasson gerrisophaga (Doutt) 1949 is the only 

 hymenopteron, other than one braconid species sus- 

 pected of having aquatic habits, to be recorded from 

 California. Doutt (1949) records the species from Lake 

 Britton, Shasta County, and from El Cerrito, Contra 

 Costa County. It has been reared from eggs of Gerris 

 sp., but the possible aquatic habits of this parasite 

 are undetermined. 



Family TRICHOGRAMMATIDAE 



The trichogrammatid genera which include adults of 

 aquatic habit are Prestwichia, Hydrophylita, and pos- 

 sibly Trichogramma. 



Several aquatic Hymenoptera which were found 

 originally in Europe were later discovered in North 



