THE INSECT WORLD. 



389 



increase come in is not entirely clear in all cases. Take, for 

 instance, the cabbage butterfly already spoken of. I have, in 

 collecting chrysalids in spring, found scarcely one in twenty that 

 was living, and from which I obtained a butterfly. All the others 

 produced parasites, chiefly the little Chalcidid already spoken of : 

 hundreds of them for every butterfly ! It would seem, then, as 

 if there were parasites enough here to attack every caterpillar 

 that hatched from the eggs of this first brood ; yet somehow 

 they seem to be almost entirely free, and the butterflies increase 

 normally until after midsummer. It seems almost impossible, in 

 fact, to get a parasitized larva until August or September, and not 

 until we get the last brood of caterpillars do the parasites seem to 

 resume activity, after all the injury has been done to the cabbage 

 crop. Perhaps ninety per cent, of all the caterpillars will be 

 found infested at this time, and a mere fragment of the brood 

 comes to maturity the following spring. 



We are unfamiliar with the complete life history of most of 

 these little species, and, indeed, a great many yet remain to be 

 described. It would be rash to say that we can never use them 

 for our own purpose, — that is, in checking injurious species ; but 

 if so, it is certain that we must know very much more about 

 them than we do at present. 



A very curious creature sometimes found flying through open 

 woods is the Pelecinus polytiirator, for v/hich the family Pelecin- 

 idcB has been established. The female is remarkable for the length 

 of its slender abdo- 

 men, each of the joints Fig. 448. 

 being almost as long 

 as the head and body, 

 and the entire insect 

 is sometimes nearly 

 four inches in length, 

 the abdomen alone 

 - measuring more than 

 three. The insect is 



so very odd and so Pelednus polyturator, male and female. 



often noticed that it 



is mentioned here to answer a frequently asked question as to 

 its character. It is not at all rare in some localities, but its habits 



