G Transactions of the Soviet//. 



character, though I am not prepared to formulate any homologies 

 with typical forms such as Pcriplaneta or Forficula (plate I. figs. 

 1,2. 



The palpi of the females in Culex are practically three-jointed, 

 while in the males they are usually more developed and are four- 

 jointed. The process of degeneration can be seen in 0. annulipes 

 Mg., where an atrophied joint is found on the distal end, making a 

 fourth joint, the usual number in the Nemocera (plate II. fig. 19). 

 Similar conditions exist in C. dorsalis Mg., and also in a 

 mosquito from Perak, Dcsvoidia ventralis. This atrophying joint 

 is also found in similar situations on the palpi, both labial and 

 maxillary, of Forficula, and in the latter case seem to have some 

 particular function, as they bear minute sense-organs on the tip. 



The Transatlantic stories of mosquito bites are often suspected 

 <>f exaggeration ; yet it is curious that the maxilla? of a species 

 raptured at Windsor, N.S., are far more barbed and stronger than 

 our C. pipiens L., or C. annulipes Mg. The labium is thicker than 

 that of G. pipiens, and is considerably shorter than that of C. 

 annulipes (plate II. figs. 20, 21). 



The pharyngeal pump in Asilus is situated in the same position, 

 but differs from that in Culex, in consisting of only two plates, the 

 upper fitting into the raised sides of the lower, and connected with 

 it at all points by a membrane. Both plates are somewhat circular 

 and send out a process at the posterior end. The upper plate at 

 Ihis posterior end broadens out, and is held by the sides of the 

 lower plate, which overlaps, making a kind of articulation ; and 

 the other portion of the upper plate is free to move, and is raised 



EXPLANATION OF PLATE III. 



Fig. 38. — Tropin of Phora curvinervis Beck. 9'. Dorsal view. The wide spread- 

 ing of the paraglossse is as the parts appear in a preparation mounted 

 with pressure. I think the natural position is like that of the male in 

 • fig. 39. 



,. 39. — Labium of ['.curvinervis $. Seen from the ventral side, and showing 

 the mentum. 



,, 40. — Hypopharynx of P. curvinervis i. 



,, 41. — Labrum of P. curvinervis 6 ■ To show how remarkably this part differs 

 in the sexes. 



.. 4:2. — Palpus of P. curvinervis £ . 



.. 43. — Labrum of Phora lutea Mg. (Aphiochseta) 9 . 



.. 44 — Hypopharynx of P. lutea J . 



.. 45. — Fused lacinise of the maxillae and teeth from the paraglossia? of /'. 

 lutea 9 . 



.. 46.— Palpus of P. lutea 9 . 



„ 47. — Labrum of Phora incrassata Mg. ? . Dorsal view. 



„ 48. — Labrum of P. incrassata £ . Dissected out and seen from underneath, 

 when the complicated folds of the double plate can be seen. 



,, 49. — Mentum of P. incrassata £ . The sides are bent over, indicated by the 

 shading in the drawing. • 



,, 50. — Labrum of Conicera atra Mg. 9 . Dorsal view. 



,, 51. — Palpus of C. atra 9 . 



,, 52. — Labrum of Phora ruficornis Mg. J . Dorsal view. 



