l.JU 



PSVLHE. 



[January — February 1KS4. 



the wilil stia\vben\- from time iiiiiiic- 

 moiial. 



One would say that here were all the 

 conditions of a most determined sting;gle 

 for existence, in which one or more ot 

 these species must succumb. It is in- 

 deed interesting to see how the issue 

 is evaded, and an adjustment reached by 

 which competition is reduced to a mini- 

 mum. The Colaspis larva makes the 

 earliest attack upon the plant, beginninu; 

 its work upon the root certainly as early 

 as the first of ISIay (half-grown indi- 

 \ icUials having been taken on the I5tli). 

 and liiiishing in June, all being of full 

 size and preparing to pupate bv tiie end 

 of that month. Next comes Paria. in 

 Julv and August, neither extreme of 

 its period being exactly defined by our 

 observations : and finally comes Scelo. 

 doiita^ adidts of which were copulating 

 on I July, young larv;ie occurring 7 Au- 

 gust. As far as now known, tiie Scelo- 

 doiita larva is left in undisturbed pos- 

 session during the remainder of the 

 year: although there is a lireak in our 

 observations for October. Certainh by 

 November il lias completed its work, 

 and retired, full-grown, and rea<lv to 

 transform, into its subterranean cell. 



It seems clear, furthermore, that this 

 curious succession of periods i.s related 



to a difference of habit with respect to 

 hibernation. Undoubtedly Scelodonta 

 winters as a larva, and Paria as an 

 adult-. As Colaspis larvae were only 

 half-grown on 15 May. they \ery proba" 

 blv hatched from the egg that spring; 

 and as the adult Colaspis emerged about 

 two months before the new brood of 

 Paria. it seems hardly possible that 

 both could have deyelojjed from eggs 

 laid that spring ; but it is much more 

 likely that Calaspis hibernates in the 

 egg. On this h\ ]5othesis. we shall liave 

 the eggs of Colaspis deposited in au- 

 tumn, those of 7'aria in spring, and 

 those of Scelodonta in midMunmer. the 

 first species hibernating in the egg. tiie 

 second as an adult, and the third as 

 full-grown larva. \\ ith the necessary re- 

 sult that their attacks upon their common 

 food plant are deli\ered successively. 



The immense advantage deri\ed from 

 this arrangement is evident, when we 

 reflect that by this means as many of 

 rafii of the species are fed upon the sur- 

 plus structures and supernumerary in- 

 dividuals of the strawberry (that plant 

 being a continuous grower), as it would 

 be possible to maintain of all three if 

 they came into simultaneous competi- 

 lion. 



COLLECTION AM) I'KLSKRNW TION OF DIPTERA. 



V.\ SAMl'KI. \\ l:\l)i:i,l, WII.I.ISTON. NKW IIAV: 



I ONN. 



l-'rom tle;ulv purchased experience I 

 have learned tiie necessity of care in 

 the collection and preservation of into- 

 mological specimens, and it ma\ be 



that a tew iiinls will lie ot ser\ ice to 

 llie collectors of diptera and similar 

 insects. 



For collecting 1 use a c\ auide-bottle. 



