1884.] 275 



an example of Ch. Zelleri, Schneider, but this has a wide range in Southern Europe, 

 and is probably scarcely more than a variety of prasina, Burm. — E,. McLachlan, 

 Lewisham, London : April \2th, 1884. 



Alleged breeding of Trypeta alternata, Fall., from Impatiens {ante p. 163). — I 

 have just received a letter from Mr. Hodgkinson on the above subject, from which 

 it appears that he threw the mined leaves of Impatiens noli-me-tangere " and hips of 

 rose together " in his greenhouse, and when the imagos of Trypeta appeared, in- 

 ferred that they were from the larvse he saw in the balsam-leaves. It seems clear, 

 therefore, that the Trypeta were derived from their known food-plant, the hips. 

 Mr. H. purposes looking up the Impatiens-\iivL\\x\g larvae this year, so we may hope 

 to learn what it will yield. — J. E. Fletciiee, Worcester : April, 1884 



The infuence of extreme cold on the Phylloxera of the vine. — In the Transactions 

 of the Hungarian Academic des Sciences, 1883, Dr. G-eza de Horvath has an article 

 giving the result of his experiments on this subject, from wliich we make the follow- 

 ing extract : — " It is known that insects in general are endowed with great vitality, 

 and that they can often endure cold by which many other animals and plants are 

 killed. In the spring, caterpillars are often found quite alive, which have hibernated 

 under shrubs destroyed by the winter." After adverting to the experience of M. J. 

 Fallou with eggs of Bombyx neustria, which sustained the temperature of — 26° C. ; 

 of M. J. Lichtenstein with divers Aphides, at — 11° and — 12° C. ; and of M. Girard 

 with the Phylloxera of the vine, at — 6° to — 10° for several days — all without detriment 

 to the insects — he continues with the narration of his own experiments : " On the 

 4th of February, I grubbed up in the experimental ground of the Hungarian 

 Phylloxera-stviiion at Farkasd (dept. of Pest) some old vine-stocks, which were 

 severely attacked. These stocks, of which the roots were covered with Phylloxera, 

 remained on the surface of the cleared ground ; on the 22nd February, that is 18 

 days afterwards, I examined the roots, with the expectation that the Phylloxera 

 would all be dead. But what was my surprise when I discovered on one stock, on a 

 little branched root, about 2 mm. in diameter, a Phylloxera living in a small group 

 of five dead ones. This example was living in its winter sleep, but it was distinguish- 

 able at once from its dead companions ; when taken into a heated room it soon 

 recovered, and four hours after it began to move and walk. This hibernating insect 

 then had been for 18 days in the open air, exposed on a place open on all sides to 

 cold, wind, snow, fog, and sunshine, and yet it remained alive." 



"The temperature fell evei-y night below zero, once it was — 8°, twice — 9°, once — 

 10°, and once — 12° C. If in the winter the soil is frozen, it is certain that many 

 Phylloxera will be killed, but there remain a large number, and that not only in deep 

 situations where the frost does not penetrate. I have often obsei'ved living 

 Phylloxera even in upper strata of frozen soil, and more than once I have found in 

 hard, frozen ground, at a depth of 10 centimetres, some of the insects in hibernal 

 lethargy, yet alive. To the insects which have taken refuge in the deeper strata of 

 the soil not even the most rigorous winter can do any harm." 



" It results then, that in the contest with Phylloxera the insecticidal action of 

 cold and the frosts of winter cannot be absolutely counted upon to aid." 



