EXPERIMENT STATION BULLETINS. 



273 



of kerosene to twelve and one half of the soap solution. Thus with our 

 present light, we recommend, a one fifteenth kerosene emulsion and, if 

 necessary, a little stronger pyrethro-kerosene emulsion, one part of kero- 

 sene to twelve of the soap solution. This, of course, implies that the 

 emulsion shall be perfect. There must be no free oil. 



THE OAK CATERPILLAR. 



This caterpillar, Edema albifrons A. & S., we find in not very conspic- 

 uous numbers each year. This season it has come in armies in nearly all 

 portions of central and southern Michigan, so that it has been repeatedly 

 referred to as the "Army Worm." This is a Bombycid or silk moth, while 

 the old army worm, Leucania unipuncta, Haw., is a Noctuid moth. The 

 caterpillars and moths are wide apart in relationship and appearance. The 

 true army worm feeds on the cereals, this on the oak. Environment is 

 often kind to the army worm, so that it frequently comes upon us in armies 

 while never before have we known of this oak caterpillar appearing in such 

 multitudes. This insect may well be called the White Oak Caterpillar, 

 though it feeds to a less degree on other oaks and on maple, beech, and elm, 

 and very rarely on hawthorn and apple. Many of our white oak forests 

 in central Michigan have been stripped of leaves the present season, so 

 that they are as bare as in late spring after the old leaves have fallen. 



The moth (Fig. 4) comes in June, and lays her eggs on the leaves of the 

 trees; the larvae feed in late August and September. This year they were 

 so common that bare ground underneath the trees was often fairly paved 

 with the small shot-like fecal pellets. As the larvae become fully grown, 

 (about Sept. 15 in this locality,) the caterpillars eat off the stems so that 

 the ground beneath the trees becomes carpeted with the fallen leaves. 

 Many caterpillars fall to the ground with the leaves, and then seek some 

 suitable place in which to spin their cocoons and pupate. 



Description of Larvos. The caterpillar (Fig. 3) is very easily known by 

 its very prominent reddish brown head, and a conspicuous red, often yellow, 

 hump on the next to the last, or eleventh, segment. It is striped 

 longitudinally with yellow, black, and white lines. The four yellow 

 lines, which are often tinged with orange, are widest. These are 

 lateral, and subdorsal, and so arranged as to divide the upper half 

 of the caterpillar into three nearly equal stripes, which are marked 

 with narrow alternating lines of white and black. The dorsal 

 stripes have five black lines and four white ones. The black ones 

 are widest and somewhat broken. The stripes between the yellow 

 lines on each side have four white and three black lines, and here 

 the white lines are widest, especially the two inner ones. The 

 black lines are somewhat broken, and the white ones dotted with 

 black. The spiracles are in the lateral yellow bands. The legs, 

 under surface, all below the lateral yellow bands, segment behind 

 the red hump, and the anal plate are yellowish white; and all but 

 the legs and anal plate are lined or dotted with black. The mature 

 larva is four cm. (1.6 inches) in length. 



Fig. 3. 



DESCRIPTION OF THE MOTH. 



The larva pupates between the leaves, or in some crevice, in very slight 

 cocoons. The pupa is finely punctured. The moth (fig. 4.) is gray with , 

 35 



