486 



OTHER BLOOD-SUCKING FLIES 



Fig. 225. Mouthparts of a tahauid; hyp. 

 hypopharynx: lab., labium; label., labolluiii 

 labr. op., labruni-cpipharyn.\: niaiid., nuindiblc 

 max., maxilla: max. p., maxillary palpus. 



deliberate and persistent in their feeding and are not easily dis- 

 turbed when they liave begun to suck blood. The thorax is 

 relatively long, and the wings are large and e.xpansive and usually 

 hold at a broad angle to the body, as shown in Fig. 227. The 

 markings of the wings usually give the easiest means of identi- 

 fication of the genera. Of 

 the four most important 

 g{'iuM-a as human pests, 

 Tdhanus (Fig. 224) is of 

 large size and has clear 

 or smok}' wings, with no 

 spots or a few small scat- 

 tered ones; Pangonia 

 (Fig. 220) also has clear 

 or smoky wings but can 

 !)(' distinguished by the 

 long proboscis; Hcematopota is of moderate size and has wings 

 with profuse scroll-like markings; and Chrysops, the species of 

 which are often small, even smaller than a housefly, has a con- 

 spicuous black band on 

 the wing (Fig. 227). 



Life History. — ^All the 

 taijanids breed in water 

 or in damj) places. The 

 eggs (Fig. 224C), several 

 lumdred in number, are 

 laid in definitely shaped 

 masses on the leaves of 

 marsh or water plants, 

 on the leaves or twigs 

 of trees overhanging 



water, or in crevices of Fk;. 220. .\ lonn-bcakcil tal)aiii(l, runwrnin 

 rocks along the sides of ruppcllU. of oa.stom .\fricu. X 2. (.\ftor Castol- 



laiii and Chalmers.) 



streams. I lie eggs are 



white wlicii laid, l)ut soon turn dark. They are dejwsitcd during 

 the summer and under favoral)le circumstances hatch in iVoin five 

 to seven days. The newly hatch(Ml larwe fall into llu^ watci- in- 

 to wet ground or decaying vegetation such as occurs around ilie 

 cfiges of nuirshes, in sphagnum i)Ogs, in decaying logs, etc. Tlu; 

 larva; (Fig. 22 ID) are cylindrical legless creatures, pointed at 



