Fig. 14:20. Tendipedidae adults, a-c, male genitalia: a, 

 Cricofopus; b, Tendipes; c, Calopsectra; d-l, Wings: d, Boreoch- 

 lus; e, Chasmaronotus; f, Diamesa; g, Metriocnemus; h, Penta- 

 neura; i, Polypedilum; ;', Corynoneuro (cl, clavus; fv, false vein); 

 k, Calopsectra; I, Cricofopus (al, anal lobe; fMC, mediocubital 

 fork; sq, squama) (a-i,k, Johannsen, 1952; /',/, Tolinaga, 1936). 



with the last larval skin loosely attached (fig. 14:35c), 

 sometimes formed in a silken cocoon or gelatinous 

 case (fig. 14:27c); the leg sheaths are free from the 

 body and do not project far beyond the tips of the 

 wing cases; usually there is a functional prothoracic 

 respiratory organ; the body is rarely strongly arched 

 (fig. 14:22i), and ends caudally in a pair of pointed 

 (fig. 14:22A) or oval processes or in a two-lobed, 

 unribbed, swimming paddle which often bears a fringe 

 of hairs or slender filaments (fig. 14:34£). The eggs 

 are usually enclosed in a gelatinous string which may' 

 in turn be deposited in a gelatinous mass whose 

 structure may vary with the species in its spiral ar- 

 rangement, convolutions, and the like (figs. 14:28c, e; 

 14:29A; 14:35z). 



The life history may vary considerably; some spec- 

 ies breeding in warm water may have a number of 

 generations a year, whereas the same species breed- 

 ing in cold lake bottoms may require a year for 

 emergence; still other species may have but one 

 generation a year. Feeding habits differ widely; most 



407 

 Wirth and Stone: Diptera 



of the Pelopiinae and some Tendipodini are preda- 

 ceous, chiefly on other tondipodid larva, but in gen- 

 eral other species are detritus or plankton feeders. 

 Walshe (1951) has reported in detail the habits of 

 several genera which habitually spin a salivary net 

 (fig. 14:26o) to catch plankton and detritus, devouring 

 the net and its contents at regular intervals. She 

 (1950) has also investigated the function of hemo- 

 globin in the respiration of bloodworms, concluding 

 that it may enable the larvae to continue active feed- 

 ing under relatively anaerobic conditions. It may act 

 in oxygen transport at very low oxygen concentrations, 

 thereby enabling continued respiratory irrigation, and 

 it may greatly increase the rate of recovery from 

 periods of oxygen lack, making such recovery pos- 

 sible even under adverse respiratory conditions. 



The larvae pupate in their larval tunnels or cases 

 and come to the surface of the water only slightly 

 before the imago emerges. Advantage may be taken of 

 this fact to place floating conical traps at the water 

 surface over the habitat in which the larvae breed, to 

 capture emerging adults together with their pupal 

 skins. Thence by bottom-dredging larvae and pupae 

 with larval skins attached, a complete, correlated 

 series of specimens can be obtained by which each 

 species can be identified from its respective habitat 

 and its comparative abundance determined. 



Although the importance of tendipedids in fresh- 

 water biology has long been recognized in Europe, 

 and a fairly complete system of classification of all 

 stages has been worked out by Edwards (1929), Coe 

 (1950), Chernov-sky (1948), Thienemann (1908 to date) 

 and his students Lenz (1936), Pagast (1947), Strenzke 

 (1950), and Zavrel (1947), our knowledge for the 

 rest of the world is woefully lacking. In North America 

 the classic descriptive work of Malloch (1915) is 

 sadly out of date, although Johnnsen (1952) has al- 

 most singlehandedly fought to keep our nomenclature 

 in line with that of European workers and has given 

 us, in his aquatic memoirs (1937), a remarkable set 

 of papers on our known immature stages in North 

 America. Only the North American adults of the tribe 

 Tendipedini have been given modern revision (by 

 Townes, 1945) although Hauber, Walley, and Roback 

 have published some smaller papers on limited groups. 



Keys to the North American Genera of Tendipedidae 

 Adults 



1. Posterior cross vein m-cu present (fig. 14:20A) 2 



— Posterior cross vein m-cu absent (fig. 14:20<7) 4 



2. Second branch of radius present and forked (figs. 14:1c; 

 14:20A), or absent altogether leaving but 2 radial 

 branches (fig. 14:20a") 3 



— Second branch of radius present and simple, not forked 

 (fig. 14:20/) (DIAMESEMAE) 14 



3. Second branch of radius forked (fig. 14:20A), or if 

 absent the anterior and posterior branches of radius 

 are almost in contact (PELOPIINAE) 6 



— Second branch of radius entirely absent, the anterior 

 and posterior branches of radius well separated (fig. 

 14:2(W) (PODONOMINAE) 11 



4. Front basitarsus shorter than front tibia (fig. 14:29i); 

 male dististyle folded inward (fig. 14:20a); middle and 

 hind tibial spurs not modified into combs 5 



