INSECTS IN THEIR RELATION TO FORESTRY 



1225 



firm fastening of the tip of the abdomen below. This, it 

 will be seen, holds the pupa in such a way that the 

 median longitudinal line of its body makes an acute 

 angle with the plane of the surface to which it is attached. 



Thus hangs the pupa of a Papilio! But why it should 

 apparently be obliged to be suspended in that manner, 

 while the pupa of an Argynnis — such as one of our 

 Silver-spots for example — should only be suspended by 

 the end of the abdomen, is surely difficult to explain. 



As has already been noted in a previous paragraph, the 

 larvae or cater- 

 pillars of our 

 moths and but- 

 terflies feed 

 upon the leaves 

 of trees; but 

 the beetles, up- 

 on the other 

 hand, are far 

 more destruc- 

 tive, for, as a 

 rule, they at- 

 tack the bark, 

 the true wood 

 within, and the 

 roots. An ex- 

 cellent example 

 of such insects 

 is seen in the 

 Broad - necked 

 Prionus (Prio- 

 niis laticollis) 

 of Drury. In 

 Packard's re- 

 port on Forest 

 Insects we find 

 a cut of this 

 species, with 

 figures showing 

 the larva and 

 pupa, after 

 Riley. The 

 beetle is illus- 

 trated in the 

 present article 

 in Figure 7, 

 which is from 

 life. General- 

 ly, this insect 

 is discovered living in the trunks and roots of the trees 

 known as the Balm-of-Gilead and the poplar; but Mr. F. 

 Clarkson found, many years ago, specimens of this borer 

 infesting the Black oak. He reported in the Canadian 

 Entomologist (XVI, '95) that "their presence is quickly 

 realized by the odor of the female, which is very power- 

 ful, and can readily be detected 20 feet distant. I placed 

 a female, immediately after emergence, in an uncovered 

 jar ; and wherever I positioned it, on the piazza or 

 elsewhere, the males were attracted from every direction. 



Fig. 6. ONE OF THE LOCKS ON THE GEORGETOWN CANAL IN THE EARLY SPRING OF 1919. 

 A FEW MILES WEST OF WASHINGTON, D. C, AND A FINE LOCALITY FOR COLLECTING 



Some of the finest sycamores anywhere are to be found in this region; sometimes they are seen to be 



double, as in this view. 



I captured twenty males in a very few minutes. Oak 

 Hill cannot boast of a Balm-of-Gilead or a Lombardy 

 poplar, but it is famous for its oaks ; and while it is 

 admitted that the former trees as mentioned by Harris, 

 serve as food for the larvae, my observations indisputably 

 prove that they feed also upon the roots of the oak." 

 This beetle is of a blackish brown color, shiny, and 

 exhibits no markings whatever. It is a strong flyer ; and 

 when on the ground it gets along with considerable 

 rapidity, especially when not impeded by the vegetation 



or the coarse, 

 pebbly charac- 

 ter of the 

 ground or soil. 

 F r equ ently 

 they make their 

 appearance i n 

 the streets of 

 our towns and 

 cities at night, 

 apparently at- 

 tracted by the 

 lights in the 

 streets and 

 w i n d o ws of 

 our dwellings. 

 This Prionus is 

 s hard, strong 

 beetle, requir- 

 ing a pretty 

 stiff blow to 

 crush it. Its 

 jointed antennae 

 are of a fair 

 length only, 

 though stout 

 and beautifully 

 jointed with 

 short joints. 

 When at rest, 

 each one ex- 

 hibits a gentle 

 curve outwards 

 and somewhat 

 backwards. Its 

 eyes are rather 

 large, while one 

 of its most 

 striking char- 

 acters is the unusual width of its neck, which, upon 

 either outer margin, presents a pair of pointed processes, 

 one in the middle and one occupying the supero-external 

 angle. Its outer wings or elytrae are granulated, and so 

 rather roughish ; while mesially, the ultimate segment of 

 the abdomen projects beyond them. Finally, we may say 

 that its three pairs of legs, having the same color as the 

 rest of the insect, are rather stout, but otherwise in due 

 proportion to the size of the insect. 



