THE CANADIAN ENTOMOLOGIST 87 



Notwithstanding its dark colour, it is a very inconspicuous 

 species, for it lives only on the under side of the leaves, where it 

 forms large colonies, the apterous adults lying in a single regular 

 row on each side of the midrib with the small forms crowded in 

 among them. It is surprising how many can exist in this way on 

 the lower side of one leaf. No matter how crowded they may be 

 on the under surface, they never feed on the upper surface, and 

 the leaves seem never to show the slightest effect of their presence. 

 The alate forms are very seldom found in the larger colonies, for 

 they leave the group as soon as matured to establish new ones on 

 uninfested plants. 



It has not been followed throughout an entire season. When 

 first found in November the colonies, then rather small, consisted 

 of apterous adults, young, and an occasional alate form. In 

 January almost every plant in the field bore large colonies, but 

 winged adults were very scarce. When, however, some of the infested 

 plants were transferred to a cage, winged forms appeared at once, 

 indicating that they had been developing, but leaving the parent 

 colony as soon as mature. The large colonies persisted in the field 

 and became very abundant until about the middle of March, 

 w^hen predaceous enemies began to make serious inroads upon 

 them. Previous to this the weather, while not freezing, had been 

 cool enough to suppress most insect activity. From this time. on 

 the colonies grew smaller and more scattered, for Coccinellids and 

 Syrphids became so numerous that no colony long remained, 

 unmolested. Small scattering colonies were still present at the 

 time of my last observations late in May. No sexes have been 

 found, and it is most likely that the species can winter exposed on 

 its food plant in any normal season. In evidence of this, I have 

 just received a letter from Mr. R. N. Wilson from Gainesville, 

 Florida, dated November 27, 1914, in which he states that a recent 

 cold snap froze the nut-grass back to the ground, and that the 

 aphids are not numerous, but at the same time he^ent a good 

 supply of them taken in the open. How they fare in summer, 

 when the unshaded sand is heated to 130 to 150 degrees F. by the 

 sun, I have not had opportunity to observe. 



Coccinella sanguinea and Baccha clavata were the most common 

 of the predaceous enemies though other species of Coccinellids 



