INSECT PESTS OF OHIO SHADE AND FOREST TREES 239 



found. There is, however, a distinctly dark and an equally dis- 

 tinctly light form. For an illustration of this and the following 

 stages, see Plate XXXIV. 



The pupa is a stocky brown object sharply pointed at one end 

 and found beneath the surface of the soil. 



The moth is typical of the group to which it belongs, the' 

 Sphingidae, with its strong powers of flight, heavy body and alto- 

 gether neat appearance. It is grayish-brown in color and measures 

 about 3 inches across its expanded wings. 



The eggs are pale yellowish-green, ovoid in shape, and are 

 deposited in convex masses on the underside of the leaf. As many 

 as one thousand eggs have been taken in a single mass, though the 

 average mass contains considerably less than that number. 



Life history and habits.— ^The winter is passed in the pupal 

 stage beneath the surface of the soil. After the appearance of the 

 catalpa leaves, the moths emerge and lay their eggs, and the larvae, 

 arising from the masses feed gregariously for some time. Later 

 they separate, but at no time do they lose their ravenous appetite 

 and, during the later stages of larval development, literally mow 

 the foliage from the trees. Upon reaching maturity they pass to 

 the soil, pupate and give rise to the second, or summer brood of 

 moths, which in their turn produce the second brood of caterpillars. 

 The eggs and caterpillars of the second brood are to be found in late 

 July and early August. Seemingly there are but two broods of the 

 insect per year in Ohio. 



Nature of work. — The prime injury caused by this insect is the 

 destruction of the foliage of catalpa by the larvae. Some seasons 

 this is very thorough and extensive, occasionally entire plantings 

 suffering a complete loss of their leaves, as indicated by the illus- 

 tration, Plate XXXV, Fig. 1. City shade trees may be said to be 

 more susceptible to injury than trees growing in the country; and, 

 when the insect appears in the guise of a street-tree pest, another 

 though incidental type of injury appears, viz, the soiling of side- 

 walks by its castings. In severe outbreaks, and particularly during 

 the later stages of caterpillar growth, this aspect of the situation 

 becomes an important one. 



The outbreaks of the pest are variable in intensity and inter- 

 mittency. It was unusually prevalent during 1905, 1906 and 1907 

 in some sections of southern Ohio, both as a street and as a forest 

 plantation pest ; and during the years following up to the present, 

 scarcely one has passed which has not brought to the office files 

 one or more records of its depredations. A report was received in 



