THE FLIES THAT CAUSE MYIASIS IX MAN 



63 



TpT* 



Figure 23. — Callitroga americana, 

 head of female, front view. 



Figure 24. — Callitroga ma- 

 cellaria, head of female, 

 front view. 



CALLITROGA AMERICANA (Cashing and Patton) 



The Primary Screwworm 

 (Figs. 25 and 26) 



Synonyms. — Cochliomyia americana Cushing and Patton; C. hominivorax 

 (Coquerel) of authors; C. macellaria (Fabricius) of much of the literature prior 

 to 1933, but not the true Callitroga macellaria of Fabricius. 



Recognition Characters. — Adult : This is a bluish to bluish-green species, 

 readily distinguishable from other members of the genus by the black hair on 

 the lower as well as the upper part of the parafrontalia. The basicostal scale 

 is black ; the occiput of the female is usually reddish orange to brown and rarely 

 with proclinate fronto-orbital bristles. Length 8-10 mm. Larva : This is a 

 typical muscoid maggot with a 

 cylindrical body which is truncate 

 posteriorly and encircled by bands 

 of spines on the segments. These 

 spines are large and robust, the 

 largest measuring 20 p. in the first 

 instar, 55 /x in the second, and 

 130 fi in the third : the tracheal 

 trunks leading from the posterior 

 spiracles are pigmented from the 

 juncture w i t h the spiracles 

 through half the length of the 

 last segment in the second instar, 

 and are similarly pigmented 

 through the last three or four 

 segments in the third instar. The 

 mature maggot may be as long as 

 17 mm. 



( rEOGBAPHICAL DISTRIBUTION. — 



Nearetic Region: North Carolina, 

 South Carolina, Georgia, Florida, 

 Alabama, Mississippi, Tennessee, 

 Indiana, Illinois, Kentucky, Min- 

 nesota, Wisconsin, Iowa, Mis- 

 souri, South Dakota, Nebraska, 

 Kansas, Arkansas, Louisiana, Ok- 

 lahoma, Texas, Montana, Colo- 

 rado, Utah, Nevada. New Mexico. Arizona, California. Neotropi il Region: Mex- 

 ico, Costa Rica, Panama. Canal Zone, Cuba, Haiti, Dominican Republic, Puerto 

 Rico. Virgin Islands. St. Lucia. Trinidad, Colombia. Venezuela, Biitish and French 

 Guiana, Brazil, Uruguay, Chile, Argentina. 



Figure 25.- 



■Callitroga americana. adult 

 female. 



