The Scottish Naturalist. 161 



air, either standing stationary, or thrown directly over the head, or violently 

 agitated backwards and forwards; and this is sure to be done with extra vigour 

 if they are in any way disturbed, and they seem instinctively to know when 

 anything approaches. What is the meaning of this habit? I think it is not so 

 much for fear of birds, as to scare away the ichneumons that are always 

 prowling about, and this opinion is amply borne out by the erratic way in 

 which their eggs (mostly pedunculated) are found scattered over the larvae. 

 In one larva about a dozen eggs were found on its body, in every conceivable 

 position, but the most remarkable instance observed, was one in which the 

 larva had attached to its face, directly below the eyes, four pedunculated eggs> 

 two on each side. The peduncles were fastened in some manner to the skin, 

 and the egg proper hung down loose, the whole being nearly half a-line long. 

 When discovered the larva, notwithstanding these singular appendages, ap- 

 peared quite healthy, and fed vigorously, but in a day or two began to move its 

 head about uneasily, and finally died ; but previously to this two of the ichneu- 

 mons left the egg, and fell to the ground, where they, of course, shared the 

 same fate. This fact is, however, sufficient to show the difficulty the ichneumon 

 (Tryphon ? ) must have in depositing her eggs in their proper nidus ; and it is 

 probably for the same reason that the larger species have acquired the power of 

 squirting a liquid from the pores -of the body. 



It would be interesting if some one would investigate whether the possession 

 of a bad odour or taste by an insect would deter insect depredators from prey- 

 ing upon it. We know that to a certain extent the above qualities protect then- 

 owners from birds, but judging from Mr Miiller's observations on the voracious 

 manner in which a bug f Picronierus bidensj attacked and devoured a saw- fly 

 larva which had a bad smell, it does not seem to be always the case with 

 insects. I have, however, found myself that cockroaches, which are perhaps 

 the most omniverous of all insects, would not eat lady-birds ( Coccinella ) and 

 Telephori, while they greedily devoured a large quantity of other insects, given 

 to them at the same time, many of these being small hard-bodied weevils. 



Some of the Ichneumonidce prey upon larvae in the perfect state. I once 

 observed a Pimpla attack a small sized lepidopterous larva, and devour 

 half of it before flying away.— P. Cameron, jun., Glasgow. 



Note on the Larva of Synergus.— In the April No. of this Magazine, I 

 alluded to certain inquiline larvse, which inhabited pea-shaped galls on oak leaves, 

 and pointed out that they were separated from each other by thin partitions, making 

 the gall polythalamous, so to speak. During the summer I have investigated the 

 subject further, and find that my former account is not strictly correct, bur 

 having observed the inquilines ovopositing in the galls, have been enabled there- 

 by to explain the matter, and the following is a summary of the observations 

 made. 



The Synergus lays her eggs in the gall, while it is in a soft and growing 

 state, and before the larva of the maker has left the egg. On entering their 

 larval life, the inquilines feed on the juices of the gall, and as they reach maturity, 

 form out of the woody matter, while it is still soft, these transparent partitions, 

 and thus contrive to pass the quiescent period of their lives undisturbed by con- 

 tact with one another, for that is I presume the raison d'etre, of the above 

 proceedings. They follow the same practice in many different galls, and their 

 presence seems to affect somewhat the form and size of the galls, either by 

 making them irregular in shape, or of a smaller size. The galls of Spathegaster 

 baccarum are frequently tenanted by six or seven inquilines, each in a separate 



