8fi 



BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE. 



Opius humilis Silv 



Opius humilis Silv. (PL XX, fig. 1 ) was first reared and described by 

 Silvestri from pupa? of Ceratitis capitata collected at Constantia, Cape 

 Colony, Africa, during March, 1913. This parasite does not appear 

 to be an effective factor in the control of Ceratitis capitata under 

 South African conditions. Silvestri reared only a few specimens of 

 which he had only 5 representing both sexes in a living condition 

 when he arrived at Honolulu, May 16, 1913. Although after Silvestri 



arrived at Honolulu he was able to rear 

 fresh material, the danger that the prog- 

 eny would be males only was so great that 

 3 females, with males, were liberated in 

 the coffee fields of Kona, Hawaii, on June 

 12, 1913. This precaution alone saved the 

 species from extinction in the islands, as 

 the progeny of the specimens kept in the 

 laboratory proved to be males. During 

 October, 1913, large numbers of Opius 

 humilis were recovered from Ceratitis ca- 

 pitata larvae in coffee cherries in Kona, 

 Hawaii, and it was found that the species 

 was well established. From the specimens 

 recovered from Kona, colonies were reared 

 and liberated in other parts of the islands. 

 No specimens were liberated in Honolulu 

 until December, 1913. By July, 1914, 

 humilis was found well established in the city, and by December of 

 that year data already published x prove it to have become very 

 abundant and widespread. 



Fig. 19.— Opius humilis: a, Egg 1 

 day old, length 0.45 mm.; b, egg 3 

 days old, length 0.8 mm. (Origi- 

 nal.) 



DESCRIPTION. 



Adult. — The original description of tho adult by Silvestri is as 

 follows : 



9 Body ochraceous in color, antennae brownish-fulvous, wings hyaline with the 

 veins brownish and the central part of the stigma ochraceous-ferruginous, legs with 

 pretarsi brown and the posterior tarsi also in great part brown. Head scarcely more 

 than one-third wider than long, hairy; face with a slight median carina; epistoma 

 slightly elevated; antennas a little longer than the body, with 35 segments; eyes a 

 little more than twice as long as wide, their lower margin attaining the level of the 

 superior margin of the epistoma. Mesothoracic scutum entire, smooth, with very 

 short parapsidal furrows anteriorly; transverse prescutellar sulcus with eight small 



1 Back, E. A., and Pemberton, C. E. Parasitism among the larvm of the Mediterranean fruit fly (C. 

 cafHlata) in Hawaii during 1914. Kept. Hawaii Bd. Agr. and For., Deo.. 31, 1914. 



