Feb. lo. 1919 Life History of Parasites of Briichophagus funebris 1 73 



LARVA 



The larva (fig. 7) varies from white to smoky gray, averages 1.6 mm. 

 in length, and is somewhat grublike in general shape. The head is of 

 medium size and faintly shows the eye lobes. Each eye lobe shows a 

 very fine seta. 



The thirteen body segments are subequal, the first one back of the 

 head being the largest and the others decreasing in size to the anal seg- 

 ment, which is bilobed, the upper lobe containing three very fine setae. 

 The dorsal portion of the first twelve body segments also shows indica- 

 tions of very short and fine setae in some specimens. 



Parasitic habit. — The larva of this species was found to attach itself 

 externally upon the larva of its host. In the course of a few days the 

 host larva apparently dies and the 

 parasite makes a rapid growth, 

 feeding upon the body contents 

 of the dead host. 



PUPA 



The pupa (fig. 8) is white when 

 newly formed. It is 1.6 mm. 

 long and about 0.6 mm. wide. 

 The head is placed slightly for- 

 ward and the appendages are 

 folded close to the body. The 

 entire pupa is enclosed in a thin 

 pupal skin. During the last few 

 days of the pupal period the 



pupa turns almost black. FlZZ-Trimeromicrusma- Fio. S.-Trimeromicrus 



Pupation.— The duration of «♦/«/«..- Larva. macuiatus. ■ fup^. 



the longest pupal period observed was 15 days and the shortest was 

 6 days. The average number of days in the pupa stage as observed in 

 the laboratory was 9. 



RELATIVE proportion OF SEXES 



The localities from which this species was reared showed both sexes 

 well represented. A count, made of 322 adults reared from various 

 localities, showed 85 males and 237 females, or a ratio of i male to 2.67 

 females. 



ECONOMIC IMPORTANCE 



Trimeromicrus maculatus is apparently well established in the Yuma 

 Valley of Arizona, where it was found to destroy about 7 per cent of the 

 larvae of Bruchopkagtis funebris infesting alfalfa seeds. Apparently it 

 is also well established in the Honey Lake Valley of northeastern 

 California. 



