486 



OTHER BLOOD-SUCKING FLIES 



labr.ep. 

 hyp. 



FIG. 225. Mouthparts of a tabanid; hyp. 

 hypopharynx; lab., labium; label., labellum 

 labr. ep., labrum-epipharynx ; mand., mandible 

 max., maxilla; max. p., maxillary palpus. 



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



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



relatively long, and the wings are large and expansive and usually 



held 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 

 genera as human pests, 

 Tabanus (Fig. 224) is of 

 large size and has clear 

 or smoky wings, with no 

 spots or a few small scat- 

 tered ones ; Pangonia 

 (Fig. 226) also has clear 

 or smoky wings but can 

 be 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 



tabanids breed in water 



or in damp places. The 



eggs (Fig. 224C), several 



hundred 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 

 rocks alons the Sides of 



streams. The eggs are 

 white when laid, but soon turn dark. They are deposited during 

 the summer and under favorable circumstances hatch in from five 

 to seven days. The newly hatched larvae fall into the water or 

 to wet ground or decaying vegetation such as occurs around the 

 edges of marshes, in sphagnum bogs, in decaying logs, etc. The 

 larvae (Fig. 224D) are cylindrical legless creatures, pointed at 



FIG. 226. A long-beaked tabanid, Pangonia 

 ru PP e ^^ f eastern Africa. X 2. (After Castel- 

 lani and Chalmers.) 



