Vol. XXXl] ENTOMOLOGICAL NEWS (.)<) 



morphosis usually have one or more simple eyes. The>e 

 simple eyes are located on that portion of the head where, if 

 compound eyes were present in the adult, they would be lo- 

 cated. This would seem to be an ontogenetic proof of the 

 contention of Lang and others that the compound eyes of 

 insects are formed from "an increase in the number of pri- 

 mitive eyes, and their approximation, led to the formation of 

 the compound facet eye." In the case of the adult male 

 coccid, the eyes are compound in the four generalized sub- 

 families and represented by groups of simple eyes in the 

 specialized subfamilies The number of simple eyes in each 

 group is gradually reduced with specialization until in certain 

 highly specialized wingless males, there is only a single ocellus 

 on each side of the head. This is the number found in all 

 adult and nymphal female coccids where eyes are present and 

 in the first and probably some of the later nymphal male 

 stages. A similar series of reductions can be shown from an 

 examination of different genera of Collembola. The latter 

 show a condition which is characteristic not only of nymphs 

 of all stages but of adults, while the male coccids show a con- 

 dition peculiar to the adult male alone. In the larvae of in- 

 sects the compound eyes may be represented by groups of 

 simple eyes, a single group may contain as many as twenty 

 or be limited to a single simple eye on each side of the head, 

 but the usual number is about six. The representation of 

 compound eyes by simple eyes is peculiar in this group to the 

 larval stages. 



All these various types of simple eyes, those of the Collem- 

 bola, of the coccids, and of larvae are also designated as ocelli. 

 The use of the same name for two or more structures which 

 are always different in position, whether they are different in 

 structure or not, always leads to confusion. In order to dif- 

 ferentiate between the simple eyes of the Apterygota and the 

 ocelli and simple eyes of other insects it is suggested that 

 each of the simple eyes of the Apterygota be known as an 

 ocelltila, plural ocellulae. The simple eyes of those insects 

 with an exometabolous metamorphosis, whether found in 

 nvmphs or adults, to be known as ocellanac to distint;ui>li 



