48 Observations on various Insects 



liymcnopterous insects. It appears that M. Gueiln bred, either 

 from the larvae or pupae of A. apricans, the minute fly called by 

 Haliday Calyptus, the Euhazus macrocephalus of Nees. It is full 

 one line long, of a black shining colour, with transparent wings, 

 a little iridescent, and the base of the shanks is yellow : the 

 female is armed with an oviduct longer than the body, which it 

 can plunge to the bottom of the calyx of the clover, and by means 

 of which it deposits an e^^ in the body of the larvae of theapions. 

 This parasite does not seem to be exempt from persecution, for 

 M. Guerin found with the eubazus a beautifully-coloured fly, 

 called by Walker Pteromalus pioiie, which is suspected to be 

 parasitic on the eiihaziis. 



It would be productive of incalculable benefit if some means 

 could be adopted for the destruction of the apions, as these crops 

 are of such vast importance to the grazier, both cows and sheep 

 feeding on all the trefoils, and clover being such a substantial 

 and excellent food for horses. 



We will conclude this important subject with some sensible 

 remarks from M. Herpin's Memoir relative to the destruction of 

 these weevils : — 



" Altbougli it be not always in our power to arrest the multiplication of 

 hiu-tful insects, to destroy them, or to comhat them with success, the know- 

 ledge of the alterations which they produce upon vegetation is nevertheless 

 very important, since it teaches us to learn the true cause of an evil which 

 may be attributed, but very incorrectly, to vague and inappreciable circum- 

 stances, to deleterious conditions of the atmosphere, to divers inexplicable 

 occurrences in vegetation ; it shows us the enemy that we must attack, and of 

 which we must carefully study the habits, economy, and metamorphoses, in 

 order to arrive with more certainty at the means of attaining such knowledge. 

 Kature, as I have before said, undertakes the check of the excessive multipli- 

 cation of hurtful insects — in the case of the clover-weevil, by exposing it to the 

 attacks of the brood of the Ichneumon hraconide, which destroys it. 



To these natural means, which do not always ensure us against serious 

 losses, I will add the following, wdiich, it appears to me, might be very usefully 

 employed : — 



1st. Cut early, and feed off while green, the clover crojis which are known, 

 or su])posed to be, much infested by the apion. 



2nd. Carefully avoid allowing the clover crops to remain more than two 

 years in succession on the same ground. 



3rd. Avoid also allowing the clover which is much infested by the weevil to 

 ripen and run to seed. 



4th. Alternate and vary the culture, as previously pointed out. 



5th, and lastly. AVe can produce the drying of the clover by the German 

 method, viz. fermentation, by making brown hay {foin hrun'). The alcoholic 

 vapours, the deleterious gases which arc formed during the fermentation of 

 clover stacked when green, the high temperature produced in the stack (+60 

 deg. Cent.,* according to my experiments), suffice to destroy the thousands of 

 larva? of the apion, which cannot endure so great a heat," f 



* 149° Fahrenheit. f Herpin's Memoir, p. 27. 



