GALL APHIDS OF THE ELM. 2O3 



cola Fitch. Fort Collins, July 8th, in 'cockscomb' galls on Ul- 

 inus americana. Five of the specimens examined have the cu- 

 bital (M) of fore wings simple." 



Mr. Sirrine's letter (Feb. 28, 1910) states "the most constant 

 distinction" (i. e., between uUnicola and colophoidea) "is the 

 forking of the third discoidal." 



We have then, Monell, Riley, Sirrine, Thomas, Walsh (cer- 

 tainly competent observers!) all familiar with the species, giv- 

 ing the venation with M branched and Cowen recording 5 

 specimens with M simple as though they were exceptional. 



My personal acquaintance with Colopha ulmicola is chiefly 

 limited to the following material: 



1. A slide lent me by Mr. Monell collected July 2, 1876, at 

 St. Louis. The slide was labeled "Tlielaxes xilmicola 157." 

 This material was collected before Riley's paper appeared and 

 was, Mr. Monell states, "certainly either type or co-type of the 

 genus Colopha." There are 4 winged specimens on the slide, 

 the 8 fore wings of which have M branched. Venation per- 

 fectly regular. 



2. A slide lent me by Mr. J. J. Davis on which were mounted 

 16 winged specimens collected at LeRoy, Illinois, July 10, 1907. 

 Of these 15 specimens have M of both fore wings branched, 

 and the other has M simple in one wing and an indication of 

 the distal tip of a branch in the other wing. Of the 16 speci- 

 mens 4 had irregular venation in varying degrees. 



3. A slide lent me from the Thomas collection. It contained 

 I winged specimen. M of both wings branched, Cu and A 

 of one wing also branched, and a slight stub branching from 

 Cu on the other. 



4. A vial with several galls, winged individuals and pupas 

 lent me from the Thomas Collection. Vial labeled merely "36." 



The antennas of the specimens lent me by Mr. Monell have 

 III, 0.16 mm.; IV, 0.05 mm.; V, 0.06 mm.; VI, 0.065 mni. ; 

 approximately. Camera lucida sketch of one of these antenna 

 is given in Fig. 176. The wing expanse is 3.7 mm. The an- 

 tennse of the specimens lent me by Mr. Davis have III, 0.19 

 mm. ; IV, 0.05 mm.-o.o6 mm. ; V, 0.07-0.075 mm. ; VI, 0.07 

 n-1m.-0.09 mm. A camera lucida sketch of one of these is given 

 in Fig. 178. The wing expanse is 3.6 mm. 



