THE STUDY OF INSECTS. 
446 
emerges soon afterward, and lays its eggs in the newly- 
started buds of the willow. 
There is a guest gall-gnat, Cecidomyia albovittata (C. al- 
bo-vit-ta'ta), which breeds in large numbers between the 
leaves composing the Pine-cone Willow-gall. The larvae of 
this gnat do not seem to interfere in any way with the 
development of their host, there being abundant food in the 
gall both for the owner of the gall and for its numerous 
guests. 
The Clover-leaf Midge, Cecidomyia trifolii(C. tri-fo'li-i).— 
The leaflets of white clover are sometimes infested by white 
or orange-colored mag¬ 
gots which fold the two 
halves of the leaflet 
together. From one to 
twenty of these larvae 
may be found in a single 
leaflet. When f u 11 - 
grown the larvae make 
cocoons, and undergo 
eport for 1879.) their transformations 
within the folded leaflet. In Figure 525 an infested leaf 
containing cocoons is represented natural size, also a larva 
and an adult gnat, greatly enlarged. 
The Clover-seed Midge, Cecidomyia leguminicola (C. le- 
gu-mi-nic'o-la), is a much more serious pest of clover. This 
infests both red and white clover. The larvae live in the 
heads of the clover and destroy the immature seed. When 
full-grown they drop to the ground, where they undergo 
their transformations. In some parts of this country it is 
impossible to raise clover-seed on account of this pest. 
The Hessian-fly, Cecidomyia destructor (C. de-struc'tor).— 
This is perhaps the most serious pest infesting wheat in this 
country. The larva lives at the base of a leaf between it 
and the main stalk. There are two or three broods of this 
insect in the course of the year. The larvae of the fall brood 
Fig. 525 .— Cecidomyia trifolii. (From the Author’s 
R» 
