INJURIOUS INSECTS AND OTHER LOWER ANIMALS I217 



INJURIOUS INSECTS AND OTHER LOWER ANIMALS. 

 943 - Contribution to the Life History and Anatomy of Lyda hypiotrophica. ( = Ce- 



phaleia abietis) (i). — Scheidter Fr.\nz, in ZeUschriH fur anccwamite Eniomolovie, 

 \'o\. 3, No. 1, pp. g7-ii6. Berlin, March 1916. 



Development of the eyes. — During an outbreak of Lyda hypotro- 

 phica in the course of the last few years in Swabia and Upper Franconia, 

 the Author, at different periods of the year (October, March-May) studied 

 a large number of larvae. He first classified the larvae according to their 

 colour and then counted them. He thus determined three groups of lar- 

 vae clearly distinguished from each other. 



The larvae of the first group, apart from the dark brown X on the fore- 

 head, had a head uniformly greenish brown or light brown in colour. Those 

 of the second group are distinguished by an ill-defined dark brown spot on 

 the cheeks. The larvae of the third group had an oval deep black spot 

 just above the eyes (eye spot). The larvae of the last group might also 

 exhibit a spot on the cheeks. The study made by the writer proved that 

 the oval spots of the larvae in the third group are nothing else than the 

 future eyes of the pupa and the adult. 



The writer calls them " pupal eyes ". They are found in all the larvae 

 which undergo transformation into pupae in the following spring. 



Wishing to stud}' the question more fully the writer examined a num- 

 ber of larvae of the first two groups mentioned above from the point of view 

 of the genital organs. He found that in larvae which in the spring had not 

 3^et got pupal CA^es.the genital organs had not yet developed. On the other 

 hand the larvae having " pupal eyes " all had well developed sexual or- 

 gans in March and April. 



At what time of the year do the pupal eyes appear ? The larvae ready 

 for pupation already possessed them in March ; on those which were with- 

 out these eyes and which were enclosed in a cage they were not seen to 

 appear after that time, that is, after the end of March. In some cases (17 

 larvae out of 9000 larvae studied) the " pupal eyes " were already observed 

 in October. 



The writer concludes that the pupal eyes do not always form in autumn 

 in the larvae which pupate in the following spring. 



The larvae which already showed the pupal eyes in October had well 

 developed genital organs, but the development was not so far advanced 

 as in the larvae studied in March and April. 



In practice, it is important to be able to ascertain as early as March, on 

 the basis of the " pupal eyes ", whether or not there will be a large number 

 of adult insects in the spring. 



Number of eggs. — The writer also studied the number of eggs which 

 a female can lay ; he found that the indications given on this subject by 

 the literature (maxinuim of 25) are inaccurate. 



(I) See B. July iyi6. No. 839. {Ed.). 



