AprU, '15] 



McCOLLOCH: CHINCH BUG EGG PARASITE 



253 



Tation. The first larval stage was completed in two or three days 

 while the second larval stage required from three to four days. An- 

 other day or two was required for molting and for the excretion of 

 waste. The total length of the larval stage varied from six to eight 

 days. 



The Pupa 



Formation. — Just before pupation begins the larva ceases to feed 

 and the waste matter which has accumulated within the body of the 

 larva during its growth is deposited at the posterior end of the host 

 egg. In a short time the bodj^ begins to constrict between the thorax 

 and the abdomen. Subsequently the eye spots begin to appear. In 

 a day or two the appendages begin to appear and pigmentation becomes 

 apparent in the head, thorax, and body (Fig. 11, D). The trans- 

 formation is completed in about eleven daj^s and the adult emerges 

 shortly after. 



Length of Stage. — The pupal stage covers about three-fourths of 

 the length of the life cycle. During August and early September a 

 number of pupae under constant observation required from eleven to 

 thirteen days to complete this stage. 



The Adult 



Description. — The adult form (Figure 12) was described last year 

 by Mr. A. B. Gahan,^ entomological assistant of the United States 

 Bureau of Entomology and his description was given in the previous 

 paper. 



Fig. 12 — Eumicrosoma henefica; adult. Greatly enlarged (After Gahan). 



During the past summer a melanic form was reared in the fourth 

 generation which differed from the form described by Mr. Gahan in 

 that the entire body was black. By crossing mth the normal form 

 it was possible to carry this form through the remaining generations. 

 During this time eighty-six black females and sixty black males were 

 reared. On August 19 a black male was reared from a chinch bug egg 

 collected in the field. 



1 Gahan, A. B., 1914. New Hymenoptera from North iVmerica. Proc. U. S. Nat. 

 Mus., Vol. 46, pp. 442^3. 



