I.] APPENDIX, 41 



II. Neuroptera. 



Phryganids ' live in the imago stage for at least a week and 

 probably longer, apparently without taking food ' (letter from 

 Dr. Hagen). According to the latest researches Phryganea 

 grandis ^ never contains food in its alimentary canal, but only 

 air, although it contains the latter in such quantities that the 

 anterior end of the chylific ventricle is dilated by it. 



III. Strepsiptera. 



The larva requires for its development a rather shorter time 

 than that which is necessary for the grub of the bee into the 

 body of which it has bored. The pupa stage lasts eight to ten 

 days. The male, which flies about in a most impetuous 

 manner, lives only two to three hours, while the female lives 

 for some days. Possibly the pairing does not take place until 

 the female is two to three days old. The viviparous female 

 seems to produce young only once in a lifetime, and then dies : 

 it is at present uncertain whether she also produces young 

 parthenogenetically (cf. Siebold, ' Ueber Paedogenesis der 

 Strepsipteren,' Zeitschr. f. wissensch. ZooL, Band XX, 1870J. 



IV. Hemiptera. 



Aphis. Bonnet (' Observations sur les Pucerons,' Paris, 

 1745) had a parthenogenetic female of Aphis euonymi in his 

 possession for thirty-one days, from its birth, during which 

 time it brought forth ninety-five larvae. Gleichen kept a par- 

 thenogenetic female of Aphis inali fifteen to twenty-three days. 



Aphis foliorum idmi. The mother of a colony which leaves 

 the egg in May is 2!" long at the end of July : it therefore lives 

 for at least two and a half months (De Geer, ' Abhandlungen 

 zur Geschichte der Insekten,' 1783, III. p. 53). 



Phylloxera vastatrix. The males are merely ephemeral 

 sexual organisms, they have no proboscis and no alimentary 

 canal, and die immediately after fertilizing the female. 



Pemphigus terebinthi. The male as well as the female sexual 

 individuals are wingless and without a proboscis ; they cannot 

 take food, and consequently live but a short time — far shorter 



^ Imhof, ' Beitrage zur Anatomic der Pcrla maxima^ Inaug. Diss., 

 Aarau, 1881. 



