NOTES, CAPTURES, ETC. 180 



of observing great devastations on tlie fir trees in tlie neighbourhood of 

 Vienna by a species of sawlly (Tenthredo rufa. King.) .... Fortunately, 

 in the nidnlh of May, a moderate frost set in, and thousands of the larvae 

 were seen hanging to the twigs, scorched." Kirby and Spence, it will be 

 remembered, has the following, on " the subject of Hybernation " : — " Many 

 insects, thougli able to sustain a degree of cold sufficient to induce torpidity, 

 would be destroyed by the freezing temperature, to avoid which they pene- 

 trate into the ground, or hide themselves under non-conducting substances; 

 and there can be little doubt that it is with this view that so many species, 

 while pupfe, are thus secured from cold by cocoons of silk or other 

 materials." The case of some hybernating larvce I take to be somewhat 

 different, according to the editorial remarks : they have without doubt 

 *' inherited " the power, originally given them, of hybernating from some 

 peculiar state of tbeir formation. Is it not the case that other hybernating 

 larv8e, those which conceal themselves, are liable to destruction by frosts, 

 when they have been tempted forth by unusually mild weather very early 

 in the season ? It is well known how sensitive Lepidoptera are to changes 

 of temperature. Might not some of their larvae escape the effects of summer 

 frosts by concealing themselves ; whilst others, which had not taken sufficient 

 protection, be destroyed? — T. B. Jeffeuys ; Clevedon, June 10, 1889. 



Migration of LEtnooPTEHA. — Previous to the 1st of June I had not 

 seen a single hybernated Vanessa cardui nor one Plusia gaviina in Surrey, 

 where I have collected several times weekly since the season opened. On 

 that day one V. cardui was captured, but on the ord of June V. cardui was 

 abundant, in fact hundreds were seen, as were P. gamina. Both species 

 gradually disappeared during the week, and were afterwards only occasionally 

 to be observed. There had been a steady south-cast wind for the three 

 days before June 1st. — John T. Carrington. 



Migration of Dragonflies. — In a note recently received from Mr. H. 



Giitke, of Heligoland, he says, "Have you had any arrival of dragonflies, 



LibeUula quadr'qmnctata ? Here, on May 21st and 2'-ind, they swarmed by 



the million, and continued to the 26th, when the wind became northerly, 



and next morning not a single one was to be seen." It will be interesting 



to learn if any have been observed on our east coast, or on the light-vessels 



in the North Sea. — John Cokdeaux ; Great Cotes, Ulceby, June ], 1889. 

 » 



Spring Insects in Middleskx. — In reference to the month that ends 



to-day, the earlier appeaiance of insects this season as compared with last 



will no doubt be remarked on. The earliest date at which I noticed 



Neuroptera, Agrionida3, and LibeUula depressa was May 19th, about 



Belmont and Canons Wood Park, between Harrow and Stanniore. Up to 



May 25lh Diptera were very abundant, and Kiiipis tessellata notably so. 



What a number of other common species — as the blue-bottle, dungfly, 



daddy long-legs, &c. — fall victims to this insect. The cold and wet of the 



last four or live days h'^s materially diminished the number of insects 



generally. The genera Eristalis and SyrpJius have been well represented ; 



Bibio marci and Leptis scolopaceus have likewise been observed, but are not 



common. Respecting Hymenoptera, I have seen very few wasps as yet, 



far fewer than last year. The fact that I captured fully twenty females 



List spring, thereby preventing twenty nests, may have had something to 



do with their comparative rarity at Cricklewood this season. Bouibi, again. 



