22§ KEPOKT OF THE COMMISSIONER OF AGEICULTURE. 



greatest moment that the eggs be kept below the hatching temperature 

 uutii the fohage on which the worms are to feed is developing and all 

 danger from late frosts is at an end. The period of hibernation may be 

 lengthened by keeping the eggs in a cool, dry cellar, with a northerly 

 exposure, and in general this will sufiice. But in such a case the tem- 

 perature is more or less variable, and the embryo may have been started 

 in its development only to be checked by renewed cold. When kept at 

 a uniform low temperature, after having once been cooled, development 

 is imperceptible, and when afterward exposed to the proper hatchiug 

 conditions, the resultant worms will prove more vigorous. Some ex- 

 jieriments made in Italy during the last few years seem to indicate that 

 additional vigor will be imparted to the race if the eggs are kept at a 

 rather high temperature during the prehibernal period, and that it may 

 be well to prolong this period artificially up to the first of January.* 

 These experiments, however, have led as yet to no wide application of 

 the process. 



When small lots of eggs are to be wintered, they may be placed in 

 ordinary boxes in the cellar, care being taken to observe the precautions 

 noted above as to ventilation, humidity, and temperature. They should 

 also be protected from rats, ants, and other vermin. But where great 

 quantities are to be stored it will be well worth while to construct 

 special hibernating boxes, where the requisite conditions may be regu- 

 lated with nicety and j)recision. Such an one has been constructed dur- 

 ing the past summer for this office, and it is hoped by its aid that eggs 

 may be kept from hatchiug until well into the summer. It is unneces- 

 sary, however, to give a description of it here, though in our next an- 

 nual report it may prove worth while to summarize the results obtained 

 from eggs wintered in it. 



In preijaring this article, we have profited largely by the work of M: 

 Pasteur upon the diseases of Silk-worms, and upon the "Lessons" of M. 

 Maillot, director of the French sericultural station at Montpellier. We 

 would recommend this latter work to the careful attention of all silk- 

 raisers acquainted with the French language. On account of their ex- 

 cellence we have copied from Pasteur the figures of Plates II and III, 

 and from Eoman's "Manuel du Magnanier," Fig. 1, of Plate lY. 



MISGELLAKEOUS INSECTS. 



DESTEUCTIYB LOCUSTS, OR "GEASSHOPPEES." 



Order Okthopteraj Family Acridid^. 



These insects have occupied rather more than their usual share of 

 r.otice during the year, as there has not only been a good deal of injury 

 ihioiighout the Atlantic States by non-migratory species, but spccin.l 

 (iO\ astatioji on the Pacific coast, as also in parts of the Northwest. 



THE ROCKY MOUNTAIN LOCUST. 



{Calo])tenus spretus, Thomas,) 



hi a jiapcr read before the late meeting of the American Association 

 for the Advancement of Science, we remarked that " plausible theories 



* Soo article of Victor Eollat, copied from II Bacolono italiano into Lc Moniteur des 

 Som, Lyons, October 17, 24, 31, and November 7, 1885. 



