24 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



of Werneburg's* of the German Macrolepidoptera 3.4 per cent, hiber- 

 nated as egg, 66.9 per cent, as larvte, 28.2 per cent, as pupa?, and 1.5 

 per cent, as imagines, while in considering a single family the result stood 

 entirely difiereut. Thus all the Zygaenidse hibernated as larvse, most 

 Sphingida) as pupse, and of the butterflies 9 per cent, in the egg, 54 per 

 cent, in the larval, 28 per cent, in the pupal, and 9 per cent, in the 

 imaginal state. Thus it appears that insects which, not to take too 

 narrow a limitation of genera, belong to one and the same genus, may 

 hibernate in wholly different stages. 



Of many species of insects only the females hibernate after impreg- 

 nation in autumn, i. e., many gnats and ourcomraon paper wasp (Vespa), 

 while the honey bees tolerate no drones in their hives, so that only the 

 queen with the workers lives through the winter. 



But abnormal meteorological phenomena may so effect such changes 

 that a species of insect may hibernate in a different stage of develop- 

 ment from what is customary. Indeed there are cases where an insect 

 may, though rarely, live through the winter in another of the four 

 stages of metamorphosis than the usual one, for it has been observed 

 that the pine Gastropacha lives through the second winter as pupa. 

 {Ratzeburg : Die Forstmsekten, ii., 147, Anm.) On the other hand, it is 

 very common for caterpillars, which seek winter quarters when half 

 grown. This they have to do as very young animals. Thus the pine 

 Gastropacha hibernates after the first molt, instead of, as usual, after 

 the second. 



Insects which have generations requiring several years must natur- 

 ally hibernate several times. This may occur in the same or in different 

 stages of metamorphosis; thus, for example, the one, two to three years' 

 generation of the May fly remains as a larva in the water, while the 

 May beetle i)asses three winters as a larva, but the fourth as an imago.t 



For the following interesting remarks we are indebted to Judeich and 

 Nitsche's work on Forest Entomology : 



Diseases of trees produced by the attacks of insects. — Various deformi- 

 ties and alterations of the wood, branches, and leaves result from the 

 attacks of borers and bud and leaf devourers. Before the tree com- 

 pletely heals there is a more or less long period during which the tree 

 assumes an abnormal, morbid appearance. Such appearances in which 

 the disease affects the growth of the wood are : 1. The appearance of 

 unusual new structures, such as leaves, etc., both in form and dimensions. 

 2. The origin of repaired parts from representative growths or sleeping 

 buds. 3. The diminution of growth. 



The appearance of unusual new growths. — In general the changed 

 sickly new growths are smaller and more sparse than the normal. A 

 thinner foliage in the year after the damage is generally the result of 



*A. Werneburg. Der Schmetterling und seiii Leben. 8°. Berlin : 1854. 

 tThe foregoing remarks on insect-generations and hibernation have been trans- 

 lated from Judeich and Nitsche's valuable work on Central European Entomology. 



