THE AMERICAN ENTOMOLOGIST. 



33 



may be prevented. It is understood that 

 the recommendation to the Government 

 will be, that in connection with the author- 

 ities in British America, efforts be made to 

 restrain the extensive prairie fires in 

 autumn which are common to that region, 

 and subsequently to burn them in the 

 spring after the hatching of the young 

 locusts. This plan is believed to be feas- 

 ible, as the breeding grounds are not co- 

 extensive with the so-called Permanent 

 region, but are limited to the richer valleys, 

 plateaus and river borders within it. 



The Commission will also, it is under- 

 stood, in its forthcoming Report, recom- 

 mend to the Government a scheme for a 

 system of warning and prevention, through 

 the aid of the mounted police patrol of the 

 Dominion Government, and our Signal 

 Bureau and military posts. 



Having been favored with a transcript 

 of the subjects to be treated of in the forth- 

 coming 2nd Report of the Commission, and 

 the assignment of subjects to the respective 

 members of the Commission, I have no hes- 

 itancy in giving assurance of a volume of 

 unusual interest and value. It is to be hoped 

 that Congress will not repeat the inexcusa- 

 ble blunder of ordering of it an edition by 

 far too small to supply the demand, or for 

 the accomplishment of a main object in its 

 laborious preparation — the diffusion of the 

 needed information among those to whom 

 it could not fail of proving beneficial. 



The Commission is also occupied with 

 investigation of the Hessian-fly and the 

 Chinch-bug — each of which are chargeable 

 with annual injuries to the amount of sev- 

 eral millions of dollars. 



The investigation of the natural history 

 and habits of the Cotton-worm, commenced 

 by the Department of Agriculture last year, 

 has by direction of Congress, been trans- 

 ferred to the Entomological Commission. 

 Prof. Riley has been pursuing its study in 

 Southern Texas and in the Gulf States, 

 aided by special assistants, and it is be- 

 lieved that discoveries have recently been 

 made which will reduce the cost of destroy- 

 ing the larvae to perhaps a fourth of what 

 it has hitherto been. 



Among the special subjects of study 

 which have claimed attention lately, an 

 interesting one has been the pupation of 

 butterflies. Observations made during the 

 past year on the pupation of some of our 

 butterflies have shown us that we have been 

 at fault in accepting the account given of 

 it by Reaumur over a century ago, and re- 

 ceived and quoted by subsequent authors. 

 The most interesting operation in the pu- 

 pation of the suspensi butterflies is the 

 withdrawal of the chrysalis from the larval 

 skin, the casting off of the skin with its 

 attachment by the terminal legs to a button 

 of silk spun for the purpose by the larva, 

 and the attachment and suspension of the 

 chrysalis by its anal spine to the silk but- 

 ton. Reaumur represented it as accom- 

 plished by the chrysalis in its extensions 

 and contractions grasping the larval skin 

 between the segments, and by this means 

 raising itself until it regained the button. 

 Recently Mr. Osborne, an English Ento- 

 mologist, discovered a membrane serving 

 as a suspensory agent in the change to the 

 pupal state, and for the first, questioned 

 the account given by Reaumur. His ob- 

 servations were confirmed by those of Mr. 

 W. H. Edwards, and followed up by addi- 

 tional observations on large numbers of 

 Nymphalidse and Danaids, some of which 

 have been presented in the Canadian jEn- 

 tomologist. There seems to be no question 

 of the existence of such a membrane, and 

 that it consists of the portion of the larval 

 skin lining the region of the rectum, caught 

 upon two knobs conveniently placed for the 

 purpose. Prof. Riley, in a communication 

 to Psyche (vol. ii, p. 249) finds other means 

 of chrysalis suspension — the principal one 

 being the shed intestinal canal, and acces- 

 sory ones, the tracheal vessels of the last 

 pair of spiracles ; these Prof. Riley regards 

 as the principal agents in suspension. In 

 opposition to this Mr. Edwards considers 

 these ligaments as of but little, if any 

 service, and finds the membrane to furnish 

 all the requisite support. Additional ob- 

 servations are required to reconcile these 

 different views. 



The beds of fossil insects recently dis- 



