INSECT PESTS OF OHIO SHADE AND FOREST TREES 311 



The winter probably is passed by the female hce within tne protec- 

 tion of the cottony secretion, though it is possible that during some 

 seasons hibernation occurs in the egg stage. At any rate if the 

 females over-winter, oviposition occurs very early in the spring since 

 the writer has observed eggs as early as April 28. 



'Nature of work. — Pines attacked by this aphis become sickly, 

 the needles turn yellow, limbs may die and occasionally the entire 

 tree succumbs. As a rule, however, only smaller trees die. The 

 white patches on trunk and limbs disfigure the tree and detract 

 seriously from its appearance. 



Food plant. — The writer has never observed this insect upon 

 any other plant than the white pine. 



Distribution. — The pine bark aphid is distributed throughout 

 Ohio. It has been reported also from Connecticut, Illinois, New 

 York, Iowa, Maryland, Maine, New Jersey, Minnesota and Canada. 

 It is likely that the insect is much more widely distributed than the 

 foregoing list would indicate. 



Natural enemies. — Four lady beetles, Anatis 15-punctata Oliv., 

 Adalia bipunctata Linn., Chilocorus bivulnerus Muls. and Megilla 

 maculata De G., have been recorded as preying upon this scale. In 

 addition to these, the larvae of Syrphid flies and ant lions have also 

 been noted. 



Control. — Spraying in the spring when the first brood of young 

 is appearing is the most satisfactory control measure. For this 

 purpose, kerosene emulsion diluted at the rate of 1 part of standard 

 stock emulsion to 9 parts of water has been recommended. Nicotine 

 sulphate at the rate of 1 part to 500 parts of water with enough 

 soap added to make a suds would be a safer remedy to apply and 

 probably would yield satisfactory results. 



THE COCKSCOMB ELM GALL 



(Colophc ulmicola Fitcb ) 



Description. — The cockscomb elm galJ is illustrated in Plate 

 LVIII, Fig, 2. As the name indicates the gall has much the shape 

 and appearance of a cock's comb. During a part of the summer the 

 ^all has a decidedly red cast which contributes further toward its 

 resemblance to the comb of a cock. 



These galls are the direct result of the work of a glossy, 

 greenish-brown plant louse. The gall proper appears upon the 

 upper side of the leaf, and when the affected leaf is turned over, a 

 glit will be noted on the underside which marks the position of the 



