700 REPORT UNITED STATES GEOLOGICAL^ SURVEY. 



" By carefully watching, I have ascertained that the favorite place ta 

 which the female cousigus her eggs iu such grass is along the inner 

 base of the terminal blades where they are yet doubled. The com- 

 pressed horney ovipositor, which plays with great ease and tentative 

 motion on the two telescopic subjoints of the abdomen, * * * * jg 

 thrust in between the folded sides of the blade, and the eggs are glued 

 along the groove in rows of from five to twenty, and covered with a 

 white, glistening, adhesive fluid, which not only fastens them to each 

 other, but draws the two sides of the grass-blade close around them, so 

 that nothing but a narrow, glistening streak is visible. * * * * 

 The female, Laving once commenced to lay, is extremely active and 

 busy, especially during warm nights, and I should judge that but two 

 or three da^s are required to empty the ovaries, which have a uniform 

 development. A string of fifteen or twenty eggs is placed in position 

 in two or three minutes, and by the end of ten more I have known the 

 moth to choose another leaf, and supply it with another string. Many 

 must bo laid very soon after vegetation starts, as some moths taken in 

 the middle of April had already exhausted their supply ; yet the bulk 

 of them are not laid till toward the end of April." The hatching of the 

 larva in a uniform temperature of 75° F. takes place from the 8th to the 

 10th day after deposition. The larvte molt five times, and but three 

 days while in confinement intervened on an average between each. — 

 (Eiley's Eighth Iiei;ort.) 



In Illinois, the moth lays its eggs in April and May, from four to six 

 weeks earlier than in the Eastern States ; so the larva ap])ears earlier. 



In Missouri, from the middle of April till the middle of May, and 

 about the middle of June probably in Massachusetts, and a week later 

 in Maine, the eggs placed iu local and confined tracts of grass-land 

 hatch their young larvte, which for four weeks or thereabout feedinces- 

 santli' till full-fed on the grass around the place of their birth, straying 

 off as their forage is eaten up to fresh pastures. 



The caterpillar state lasts for about a month, when it descends inta 

 the earth and changes to a chrysalis, remaining in this state two or 

 three weeks. In Southern Missouri the moth appears about the fore 

 part of June. — (liiley.) In Xew England the moth appears iu 



It is probable, according to the observations of Mr. Kiley and myself, 

 that while the majority of the moths appear in the late summer or early 

 autumn, according to the latitude of the place where they live, a few 

 may hybernate in the pupa state iu the Middle States, and still more 

 in the Xew England States. Mr. Riley thinks that the moths may ■ 

 sometimes lay their eggs upon newly-sown fall-grain. 



We first hear of the army-worm when it is about an inch long; but 

 it has eaten up all the grass around its place of birth, and in myriads is. 

 pushing out its columns after forage. The mature larva is about an 

 inch and a half long. Its cylindrical body, divided into thirteen rings 

 becomes more contracted and wrinkled at each end, and is sparsely 

 covered with short hairs. The head is covered by a network of con- 

 fluent spots, while along the middle of the face run two lines diverging 

 at each end. A light-colored waved line just above the legs is suc- 

 ceeded by a dark one, then a light one edged with two thread-like lines; 

 while the upper part is dark, with an interrupted white threadru nning 

 exactly through the middle of the back. The prolegs, ten in number, 

 are marked on their outer middle and on their tip with black. Beneath, 

 the caterpillar is of a livid green. 



Its name is suggestive of the regular, trained way in \\^hich myriads 

 of these caterpillars march together in long, deep columns, side by side. 



