198 Psyche [December 



EXPLANATION OF PLATE. 



Fig. 1. Egg. 



1. 2. Egg-mass. 



3. Longitudinal section of stem showing position of egg at base of old bud 



scale. 



4. First instar. 



5. Second instar. 



6. Third instar. 



7. Fourth instar. 



8. Fifth instar. 



9. Adult female. 

 10. Adxilt male. 



NOTE ON THE SPECIES OF THE GENUS ACROCERA. 



By Charles W. Johnson, 

 Boston Society of National History, Boston, Mass. 



Most of the species of this genus have remained practically 

 unknown since they were described. This is undoubtedly due to 

 poor description on the one hand and to the scarcity of material 

 on the other. Since obtaining my first specimen in 1895, only 

 seventeen additional specimens have come under my observation, 

 representing perhaps seven species. The variable and vestigial 

 character of the venation offers an attractive field for study if only 

 sufficient material could be obtained. The species, so far as known, 

 parasitize the ground spiders of the genera Lycosa and Amauro- 

 bius, and no doubt a number could be obtained by raising the 

 various species of spiders of these genera. The late Dr. T. H. 

 Montgomery in conducting some studies on the Lycosids, bred a 

 number of Acrocera Jasciata, and I remember he said that he could 

 detect those which w^ere parasitized, long before there was any 

 other indication, by their weaker and more poorly constructed 

 webs, the parasite evidently affecting the functions of the spinneret. 



The brief Latin descriptions by Westwood (Trans. Ent. Soc, 

 London, V, 91, 1848), are very trying, and the positive identifica- 

 tion of some of his species seems almost impossible with so little 

 material, especially from the southern states — three of his species 

 being described from Georgia. I can therefore present only the 

 following provisional table and notes, trusting that they may lead 

 to a further study of this interesting genus: 



