162 C. G. LAMB. 



The venation is different : on micrometric measurement it is found that the ratio 



distance from small to large cross- vein . . rt .., . _ , ... 



v- 7 = ?-— -. r— = 0'42, while in D. paradoxa it is 



distance from large cross- vem to wrng-margin r 



about 062 ; also as measured along the costa we have — i — tttl t — nr = 1"6, 



° end of 2 to end of 3 



whereas in D. paradoxa it is a little over 2 ; hence the 2nd vein is proportionally 



much shorter. The free end of the 5th vein is also longer, and there is no 



darkening at all of the veins or costal border. 



The pinned specimen was so badly placed for viewing that the abdomen could 

 not be properly examined, but it was apparently very like that of the last species 

 externally. The fragmentary specimens were mounted as slides, as before 

 mentioned, and hence are not much help in description. 



Size, as last species. 



Panama : Changunda, xi, 1917, (C. B. Williams). 



[In a later communication Mr. C. B. "Williams states that from what he saw of 

 the Panama Drosophila he concluded that it was probably not a true parasite of 

 the Clastoptera, but merely an inquiline. In Trinidad, however, he collected about 

 30 spittle-masses of the same Clastoptera on Casuarina trees, and about half of these 

 contained Drosophila larvae, most of which had their heads buried in the abdomen 

 of the Clastoptera nymphs, the head being usually inserted between the dorsal 

 abdominal plates. In a letter to Mr. Williams, Mr. A. H. Sturtevant, of Columbia 

 University, New York, says : " Similar habits have been observed in Drosophila 

 inversa, Walker, in Minnesota. C. N. Ainslie (Canad. Ent. 1916, pp. 38-44) 

 reported this species (incorrectly determined as D. sigmoides, Loew) as bred from 

 pupae found in the froth of a Cercopid." — Ed.]. 



