52 BULLETIN OF THE BUREAU OF FISHERIES. 



Chironomus lobiferus. 



Fig. 26. — Diagram of a glass preparation showing the position occupied by the larva in its burrow; 

 lc, lower glass; nt, conical net; t, glass tube; u, upper glass; v, larva. 

 Fig. 27. — Diagram of the contracted conical net. 



Fig. 28 



Fig. 29 

 Fig. 30 



Fig. 31 

 Fig. 32 



— Broken labial plate. 



Orthocladius sp. 

 — Labium. 



— Mandible. 



Prodi ames a sp. 



— Maxilla; ar, articular process; c, vibrissa?; 1, lacinia; la, labium; p, palpus; st, stipes. 

 — Ventral aspect of a portion of the head; ar, articular process; c, vibrissa?; la, labium. 



Chironomus lobiferus. 

 Fig. ji- — Claw of posterior proleg. 



Fig. 34. — .Spines of anterior proleg; a, serrate spine; b, c, hooked spines; d, hairlike spine. 

 Fig. 35. — Left anterior proleg; a, hairlike spines; b, hooked spines; c, serrate spines. 

 Fig. 36. — An enlarged silken holdfast attached to a glass surface; g, a process on the side of a larval 

 burrow. 



Fig. 37. — Silken network between two larval burrows ( g, h); i, interlacing silk fibers. 



ORPHNEPHILA AMERICANA. 



Fig. 38. — View of habitat where larvje were found, west bank of Six Mile Creek, Ithaca, N. Y. ; 

 F, water level of the main stream; 1, ledges kept moist by water flowing in a small stream shown just 

 above; w, water flowing over ledges. 



Tanypus DYARI. 



Fig. 39. — Labrum; ch, chitinous plate; cp, chitinized process; se, sensory process. 



Fig. 40. — Chitinous structures of the maxilla; 1, lacinia; p, palpus. 



Fig. 41. — Ventral aspect pf the head; hy, hypopharynx; la, labial papilla; md, mandible; mx, 

 maxilla; p, maxillary palpus; r, antenna. 



Fig. 42. — Dorsal view of the labium and hypopharynx; ar, articular plate; cb, chitinous band; 

 hy, hypopharynx; la, labial process; lp, lateral hypopharyngeal process; pr, sensory process; th, 

 chitinous plate of the hypopharynx. 



Fig. 43. — Lateral view of the same. 



Fig. 44. — Dorsal view of the entire larva; br, branchial gill; c, cardiac chamber; cr, crop or pro- 

 ventriculus; g, salivary gland; m, malpighian tubule; r, retractile antenna; st, stomach or ventriculus. 



Culicoides SP. 



Fig. 45. — Dorsal view of entire larva; f, caudal filaments; g, branchial gills. 



Fig. 46. Lateral view of the head; d, salivary duct; ep, epipharynx; ey, eye spot; hy, hypo- 

 pharynx; la, labium; lb, labrum; md, mandible; mx, maxilla. 



Fig. 47. — Ventral view of the head; structures the same as shown in fig. 46. 



Fig. 48. — Dorsal view of the posterior end of the larva considerably enlarged; f, caudal filaments; 

 ff, accessory caudal filaments; g, branchial gills. Larva from sap flow in elms resembling Culicoides 

 hieroglyfthicus. 



Fig. 49. — The entire larva, dorsal view; ch, chitinous rod. 



Fig. 50. — Posterior end of the same greatly enlarged; c, caudal processes; g, branchial gills; s, 

 sets resembling caudal filaments. 



Fig. 51. — Mandible. 



Orphnephila testacea. 



Fig. 52. — Side view of entire larva showing characteristic color pattern. 



Fig. 53. — Side view of the head and proleg; ey, eye spot; la, labium; lb, labrum; md, mandible; 

 mx, maxilla; pr, proleg; r, antenna; sp, spines. 



Fig. 54. — Frontal view of the head; cl, clypial plate; la, labium; lb, labrum; md, mandible; 

 mx, maxilla; rd, rod attached to the mandible. 



Fig. 55. — Ventral aspect of the mandible. 



Fig. 56. — Dorsal-lateral aspect of the hypopharynx. 



Fig. 57. — Miscellaneous diatoms from the stomach of Orphnephila. 



