New \'ork Agricultural Experiment Station. 589 



soon change to a deep chestnut brown. Fig. 2 is from a pho- 

 tograph of several of these chrysalides. The moths come forth 

 in about two weeks. Fig. 3 is from a photograph of two of the 

 moths with tlieir wings spread, and fig. 4 of two of the moths 

 with their wings in the position which they assume when at rest. 

 Fig. 5 is from a photograph of some deformed moths. They 

 apparently lacked strength to develop properly and soon died. 

 There are probably two or three broods every year in the more 

 northern states.* It is usually only the first brood of the season, 

 however, which occurs in such unusual numbers. 



Hihernation. — The caterpillars of the last brood of the season 

 are but half grown when winter overtakes them. For protection 

 they hide away under any convenient shelter, where they become 

 very sluggish, in which condition they remain until spring. The 

 moths from this brood of caterpillars come forth quite early in 

 the season. As above noted, it is this generation of moths which, 

 under favorable circumstances, produces the vast armies of cater- 

 pillars such as we have witnessed this summer. 



Natural Enemies. 



Fortunately nature takes a hand in checking the onward march 

 of such armies as these. Judging from our observations in the 

 field, and from specimens sent us, the present generation of 

 army worms is being seriously crippled by several species of 

 parasites and predaceous insects. We have also found many of 

 the caterpillars attacked by a fatal bacterial disease which seems 

 to resemble the bacterial disease of cabbage worms. In one or 

 two instances it was estimated that twenty-five per cent, were 

 attacked by this diseas(\ Of the parasites referred to, one of the 

 most prominent is a species of Tachina fly. This active little 

 insect resembles a house i\y in general appearance. The Tachina 

 fly lays its eggs on the backs of the ill-fated caterpillars just back 

 of the head. Many caterpillars were found with three or four of 



•Note.— Since tLe above wan wriKen Ihe follo-wiri" notes who made at fl e StatioD; Lritb 

 (jf the army worm Levcania vnijniniin were observed in tbe field from the latter part of June 

 Tiutil Aufi'ist 7; Jnly 7, fullgrowii arid half-grown larvae w<rti fotiud; July 13, many of <h» 

 laiTHP were jiiipating ; July 2«, first moth emerffed in hreedinp rage; August 3, mollis alun d- 

 ant; September 24, army worms varyiug in nize from ore-half of an irrh to full gro-nn w«rm« 

 trere found under stones etc., in the field of peas rn tlie Station gioiindf". During the middle of 

 October worms \M'if si-ain fornd in the phuic field, but nopupee. 



