THE CANADIAN SPORTSMAN AND NATURAL I ST. 



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three eggs was found. We concluded to leave 

 it, for a week in order to obtain a full set, 

 Seven days later, on returning, we found only 

 six, which were slightly incubated. The con- 

 struction (if thisnesl was similar to the former. 



John Alfred Morden. 

 Hyde Park, Out. 



CHALCID PARASITES IN LARV.E OF 

 LAVERNA GLEDITSCHIELLA. 



V. T. Chambers in " Canadian Entomolo- 

 gist," vol. ix, p. 233, says — " Laverna glediis- 

 chiella is much subject to the attacks of 

 hymenopterous parasites in its larval condition. 

 Yet it is difficult to understand how this is 

 possible under the conditions of its larval life. 

 I have never been able to understand how the 

 larva; gets to the pith without leaving some 

 •trace of its patl\ from the outside ot the stem. 

 The egg must be deposited on the outside ot 

 the stem, because the ovipositor of the female 

 is too soft to be able to penetrate the bark and 

 wood to the pith. It would seem that the eggs 

 of the little chalcid parasite must be deposited 

 on the microscopic larva of the moth as soon 

 as it emerges from the egg, and before it has 

 eaten its way into the brand), because it is 

 impossible to understand how it can be done 

 afterwards, as these little parasites are them- 

 selves so small that two of them placed ei.d to 

 end would not extend from the outer surface 

 of the back of the twig to the central pith, and 

 their ovipositors are very short and not exerted." 



In elucidation ot tins problem, I am ol 

 Opinion that the egg of the parasite is not laid 

 upon the lepidopterous larva 1 ., but on (or m 

 close contiguity to) the egg of the future host, 

 and the eggs batching simultaneously, or 

 possibly those ot the parasite a little in advance, 

 the laiva ol the hymenopterous parasite 

 attach themselves to the body ol their victim, 

 into which they immediately make their way 

 and are carried into the pith inside the body 

 of the lepidopterous larva. In no other way 

 can I conceive it possible for Chalcid parasites 

 to infest the bod>es of internal feeding lame 

 of such small dimensions as those of the 

 micro -lepidoptera. RlCHARD SHIELD. 



Montreal, April, 1883. 



"CAUSES OF RARITY IN SOME SPECIES 

 OF INSECTS." 



The interesting paper on this subject by 

 Mr. Bowles, in the last number of the 



Canadian Sportsman <ni>l Naturalist, offers to 

 entomi >me valuable idea« for consid- 



eration, and drawn attention to several | 

 in connection with our insect fauna which 

 should be carefully investigated. Ckioaobas 

 jutta was mentioned a- becoming rare in the 

 vicinity ol Quebec through the draining ol the 

 swampy tract in which it- food plant- _ 

 Near this city there is but one habitat SO far 



discovered for Melitea phaeton, and this 

 very limited area. Should it be cleared and 

 drained, as has been partly done arreadj . this 



beautiful species would disappear In >ur 



local fauna. Thus in the case of species hav- 

 ing restricted habitats, we can trace the cause 

 of their disappearance, and similar causes will 

 account for the gradual extinction "l many 

 species having a wider range. As the forests 

 and marshes are cleared, many varietii 

 food plants are partly or wholy exterminated, 

 while the insects have now added t" the ii-t of 

 their enemies. Thus with a scarcity of a] 

 priale food and with additional toes to encoun- 

 ter, they are sooner or later numbered with 

 the things that are no more. The unusual 

 abundance of parasites in any year, or series ot 

 years, might in the case ot a rare species lead 

 to its extinction, but this would, probably 

 seldom occur over an extended area. Immense 

 numbers of Fanessa antiopa were destroyed 

 last season by small ichneumons, but in the 

 case of this common butterfly the result can 

 be but to cheek it lor a year or so. The effect 

 ol different seasons upon insect life has. as Mr. 

 Bowles remarks, not yet been thoroughly 

 studied,and the difioulties of doing so are very 

 great, owing to the enormous diversitj of 

 species, and that what is one's meat is another's 

 poison. 1 think we may safely predict, how- 

 ever, that after the cold, steady winter which 

 we have had, witii its abundance of snow- 

 covering the ground continually, we will have 

 an unusual number ot insects during t.ie 

 approaching season, and our collectors would 

 do well to record whether such prove.- to be 

 the case. The conditions appear to me to 

 have been very favorable, for a large propor- 

 tion of our species at least. 1 have not noticed 

 any migratory habits in our species of butter- 

 flies and am unable to say whether they have 

 much part in causing an abundance or scarcity 

 ot local lepidoptera. Vanessa J. album is 

 rare here 1 imagine, for only one specimen 

 has been captured in six years. The theory 

 of species having originated with a certain 

 vital impetus, which in some has already, and 



