ON THK NORTH AMERICAN COSSIDJS. Od 



were deposited singly and some in confused heap*, and were attached 

 to each other and to the box with a viscid substance. 



Another female was captured June 20, and in forty-eight hoars after 

 being pinned she had deposited sixty eggs, which varied somewhat in 

 color from the former. 



The Cossus after being pinned is very restive, especially while de- 

 positing her ova and bj T the constant motion of the oviposter in endeav- 

 oring to extrude the ova. The loo^e abdominal scales are removed and 

 attached to the eggs by the moist viscid fluid with which they are cov- 

 ered, and which often gives them the appearance of being clothed with 

 scales. A few of the ova collected this season have this appearance, 

 but a strong lens exposes the true condition. ('. centerensis is not so 

 prolific as some of the other species of Gosmdoe. C. robinioe Peck and 

 G. querciperda Fitch have been known to extrude upwards of three 

 hundred ova. In European species over one thousand ova have been 

 found on dissection. The ruin of whole forests of timber in which these 

 insects revel is doubtless prevented by the destruction of the eggs by 

 ants and birds, the size of the eggs being sufficient to form a tempting 

 morsel. In a state of nature the female Cossus deposits a small num- 

 ber of her ova upon each tree which she visits until her supply is ex- 

 hausted. 



This season the enlarged perforations through the bark show unmis- 

 takable evidence that the trees had been recently visited by wood- 

 peckers, which could find little difficulty in procuring an abundance of 

 full-grown larvae. 



C. centerensis is found throughout the region known as the pine bar- 

 rens, which cover an area of perhaps 12 square miles between Albany 

 and Schenectady. The soil of this region seems especially well adapted 

 to the growth of the timber which it supports. 



At the present time no correct observations have been made in ref- 

 erence to the molts of the caterpillars, but information on this subject 

 will soon be obtained from Mr. A. H. Muudt, of Illinois, who has had 

 opportunities of observing, up to the fourth molt, the caterpillars of 

 C.robinia', which are found in the willows and poplars in his vicinity. 



Cossus centerensis appears every year, and from observations and from 

 numerous examinations of the trees by actual sections during the three 

 months of the year enumerated, I am convinced that the caterpillars 

 are not fully matured until the end of the third year, when they arrive 

 at their perfect or winged state. The pupa state is comparatively 

 short, lasting less than a month before the moth appears. From figures 

 3, 4, and 5 of Plate I we see representations of caterpillars found Octo- 

 ber 14, which establish the fact beyond dispute, through observations 

 extending over many years, that it requires three full years for the cat- 

 erpillar to arrive at maturity. 



