No. 468.] THE WILLOW CONE GALL. 367 
verifications by observation in the case of the cocoons of five of 
the galls and in the case of the larvae and pup of three of them, 
I am convinced that specific differences, if any, must be looked 
for in the imagoes, for they cannot be found in the earlier stages. 
Imagoes of the makers of five bud galls were found and 
described by Walsh. I give below a table showing the differ- 
ences which he finds in them. 
Imagoes of Bud Gall Makers. 

strobiloides | strobiliscus | gnaphaloides | — rhodoides 


Species brassicoides | 
Antennal | 
oints 22-24 | 21-22 23-24 21-25 
Thoracic Hairs Dusky | Whitish Whitish | Whitish Whitish 
Length in 
| 
nches | 0.16-0.20 |0.16-0.20 | 0.12-0.15 | 0.16-0.20 
Origin of Ante- | Occasion- Always ob- | Rather Rather | Occasionally 
rior Branch of | ally obso- | solete for a | distinct distinct obsolete 
Cubital Wing lete | short space 
Vein 





The variation in the number of antennal joints makes that 
feature useless as a specific characteristic. Antenne of dried 
specimens are easily broken, but by using fresh and alcoholic 
specimens, I find that there are about the same number of joints 
in those of all the gnats which make the different galls. 
The color of thoracic hairs is the first and only distinguishing 
characteristic. I have had only five imagoes of C. s. brassicoides 
Walsh but find that the dusky hairs are present in all, while in 
the gnats from the four other galls the thoracic hairs are whitish. 
Length shows no difference except in the one case, and I 
think this cannot be considered for I found four, from one.lot 
of five imagoes from the gall S. gnaphaloides, which were fully 
0.21 inches in length, and I have found but one or two as short 
as 0.12 inches. 
As to wing venation the wings of four C. s. brassicoides Walsh 
have the origin of the anterior branch of the cubital vein dis- 
tinct. Seventeen left and eighteen right wings of C. s. strobi- 
loides Walsh gave the following results as to the origin of the 
anterior branch of the cubital vein : —- 
