354 EEPORT UPON COTTON INSECTS. 



destroyed 9,11 the foliage in the field, except a strip along the eastern fence where the 

 cotton was tall and luxuriant. The fence was skirted by forest from 60 to 80 feet high, 

 and consequently the rays of the sun did not strike the cotton until about ten o'clock. 

 I found a few worms there and eggs abundantly. My conjecture was that, as the sun 

 did not strike the cotton until the morning dew had all evaporated, the true condition 

 for hatching by solar evaporation was absent and the larger proportion of the eggs 

 remained unhatched. The explanation would be, that the egg being albuminous and 

 hence nitrogenous, as well as all eggs are, and being coated with a gelatinous or mu- 

 cous outer coat as well as a denser inner coat, the egg membrane proper would be sub- 

 ject to both the chemical and vital laws under which all germination occurs ; that is, 

 heat and moisture induces in all nitrogenous matter fermentation and decomposition, 

 and this increased heat hastens the vivification of the germ which would organize 

 under its vital law. 



Suppose, however, solar evaporation to be intensified by an artificial process, would 

 not hatching necessarily proceed more rapidly ? In the nature of things it inevitably 

 would, and as far as eggs came within its intluence they would be speedily hatched. 

 The process referred to is that of plowing land when wet, under a hot sun. The effect 

 is to destroy capillarity and expose the up-turned furrow to rapid evaporation, by which 

 means the volume of air surrounding the cotton would be loaded with vapor and the 

 temperature increased 10 or 12 F. This process effects in a short time, perhaps a 

 few minutes, what ordinary solar evaporations or telluric radiations would not effect 

 in a season. You likewise, by this bad tillage, give back to the air the fatness of the 

 earth, for you thereby extricate the valuable gases which a bounteous Heaven has 

 sent, and it really seems to me that the worm is a just retribution. 



I have repeatedly brought the egg of A letia in from the field this season and placed 

 it under the solar microscope. As seen by the naked eye, it is a minute green globule, 

 as large as a celery-seed and somewhat greener than the leaf upon which it is found. 

 [I have rarely seen more than four eggs upon any one leaf, sometimes near together, 

 but oftener far apart. All invariably attached to the under part of the leaf by a gum- 

 ming substance secreted by the mother moth in incubation.] The egg varies from a 

 deep green to an almost transparent color, according to age ; and those gathered late 

 in the fall are darker and almost black. On being broken they were found to contain 

 a translucent fluid. Under the microscope it exhibits the conical shape and curved 

 ridges, radiating from apex to base, so well described by others, and presents the ap- 

 pearance of a granulated diamond, sparkling from innumerable points. Being so mi- 

 nute I can say nothing of its internal structure, but, from its bursting under pressure, 

 knew that the investing membrane is indued with elastic power and affords to the 

 germ requisite protection ; and as it only changes color and shrivels as the season ad- 

 vances, retaining its contents clear, I am disposed to think it may survive a winter. 

 I am now testing its capability for hibernation in different modes ; have some on leaver 

 in my house, some under ground, others in boxes under earth, and others suspended 

 in the air in muslin cages. All look black except those that have hatched. As cold 

 could only affect the vitality of the germ by its intensity, and the chemical forces that 

 would promote vital activity are dormant under its influence, I conjecture that the 

 egg falling to the ground with the detritus of the plant and covered by earth would 

 remain quiescent until acted upon by its appropriate stimulus, heat and moisture, aud 

 this would not be sufficiently potential until June or July in this latitude. 



Professor Riley, in his admirable report upon the grasshopper of the West, showing 

 a degree of patient and thorough investigation rarely equaled, gives a minute descrip- 

 tion of the process of oviposition, and announces clearly the physiological law under 

 which the hatching of the egg must occur, and in his experiments, where he transferred 

 the eggs, after repeated freezing and thawing, to moist earth, intelligently consulted 

 nature and artificially produced the best condition for hatching. The moist vapor cre- 

 ated by radiated heat, permeated, perhaps, by gases, was the most propitious menstruum. 



THE CHRYSALIS. 



Many of the chrysalids brought in by me came forth perfect moths. From the shell, 

 in other cases, issued the ichneumon fly ; in some cases the sole occupant, in others the 

 co-tenant of a dead moth partly consumed. I brought them in from the field as late 

 as the 16th of November, full of vitality. To-day, January 7, 1879, 1 examined several 

 taken from boxes of earth, glass jars, and gauze cages, all placed in my piazza, in the 

 onter air, subjected to all the changes of the season, with the thermometer for the last 

 twenty-one days at or below freezing, and once or twice as low as 28 below freezing, 

 and on warming them they showed animation, and their movements became very sen- 

 sible. I have no doubt about carrying them through the winter successfully. Many 

 of our most observant planters affirm that they plow them up every spring, and find 

 them alive. Many of them perish, but enough survive to perpetuate the species. The 

 earth affords protection by concealing and by warmth in the one case protecting 

 against enemies, such as hogs, birds, &c., and in the other against inclemency of sea- 

 son. Could planters be induced to harrow their lands in winter, thereby exposing 

 them, a great majority would be destroyed. 



