84 American Midland Naturalist Monograph No. 3 



posterior pronotal and postspiracular bristles absent. Wing scales sparse, 

 short and broad. Second marginal cell of wing much shorter than its stem; a 

 slight emargination present on hind margin of wing opposite vein 5.2, and a 

 submarginal V-shaped thickening of the membrane between 5.1 and 5.2. Cross- 

 veins as in Anophelini, bent at right angles. Male Terminalia: Tenth sternite 

 with not more than two or three terminal teeth. Phallosome consisting of two 

 elongated plates, heavily sclerotized. Basistyle conical; basal lobe present, 

 bearing spines; apical lobe absent. Claspette absent. Dististyle long, slender, 

 not swollen medially. Larva: Larvae very large and predacious. Mouth brushes 

 of strong, curved, flattened setae, about 10 in number, not serrated but with 

 hooked tips. Head almost square; frontoclypeus divided by a transverse suture 

 into an anterior part and a much larger posterior part which comprises most 

 of the dorsal head surface. Mentum much broader than long. Antenna smooth, 

 cylindrical, with a minute tuft beyond middle. Hairs of thorax and abdomen 

 arising from heavily sclerotized plates; comb and pecten entirely absent. The 

 fusion of the sclerotic plates of the upper and lower lateral hairs on abdominal 

 segment VIII forms a large plate bearing strong serrated hairs in the position 

 generally occupied by a comb in other mosquitoes. 



Key to the Species 



adult males 



Fore-tarsus entirely dark scaled ....septenlrioiialis D. and K., p. 85 



Fore-tarsus with segment 2 and the basal portion of segment 3 white-scaled on one 



side - --......ruiilus Coq., p. 84 



Megarhinus rutilus Coquillett 



Megarhimis rulila Coquillett, 1896, Can. Ent., 28:44. 



ADULT FEMALE. — Indistinguishable from M. septentr'tonalis. 



ADULT MALE. — Similar to male of M. septentrionalis, but with segment 2 

 and basal portion of segment 3 of fore- and mid-tarsi white on one side, ter- 

 minalia. The male terminalia of this species appears to be indistinguishable 

 from that of M. septentrionalis (Fig. 43). 



larva. — Unknown. 



DISTRIBUTION. — Florida and Georgia (96); South Carolina (4th Sv. C. 

 Med. Lab. records, 1944, unpublished) . 



BIONOMICS. — Megarhinus rutilus breeds in rot cavities of trees, but it is 

 a rare species and very little is known of its biology. 



Megarhinus septentrionalis Dyar and Knab 



Megarhinus seplentrionalis Dyar and Knab, 1907, Jour. N. Y. Ent. Soc, 15:12. 



ADULT FEMALE. — Very large brilliantly ornamented species. Head: Probos- 

 cis long, black, tapered, the apical half strongly down-curved. Palpi about two- 

 thirds as long as proboscis, metallic dark blue to violet, with golden-yellow 



