OF WASHINGTON. 91 
tional Museum. The remaining three he had believed were lost, 
but during a recent visit to Philadelphia he succeeded in finding 
two of them in the collection of the Academy of Natural Sciences. 
This discovery enables him to correctly place in the recent system 
all but one of Wood's species as follows : 
1. Buthus biaculeatus = Centrums biaculeatus Lucas. 
2. Buthus boreus = Vejovis boreus Girard. 
3 Buthus Californicus = Centrurus vittatus Say. 
4. Buthus Carolinianus = Centrurus vittatus Saj. 
5. Buthus emarginaticeps = Hadrurus emarginaticeps W.* 
6. Buthus eustheneura = ? (type lost). 
7. Buthus exilicauda = Centrurus exilicauda W. 
8. Buthus hirsutus = Hadrurus hirsutus W. (Thorell). 
9. Buthus Lesueurii = Diplocentrus Lesueurii G. 
10. Buthus punctipalpi = Vejovis punctipalpis W. 
11. Buthus spinigerus = Vejovis spiniger W. 
12. Centrurus phaeodactylus = Uroctonus phaeodactylus W. 
13. Scorpio Allenii = Broteas Allenii W. 
Mr. Smith exhibited a section of Abies Douglasi, from Cali- 
fornia, with the burrows of a Longicorn beetle, Notorhina aspera, 
and read a letter from Mr. L. E. Ricksecker in regard to the ovipo- 
sition of this species. 
Mr. Howard spoke on retardation in the development of Bom- 
bycidce. He instanced European cases of such retardation, and 
narrated that in October, 1885, tw r o cocoons of Samia cecropia 
were received by a lady friend of his. About two months ago 
these cocoons were cut open, and the pupae were still alive, so 
that the imagos would probably not appear before next year. 
In discussing this communication, Mr. Smith stated that a re- 
tardation of one year has frequently been observed in most of our 
large Saturniidce and in many Sphingida. Mr. Ashmead said 
that he had kept a Cynipid gall for two years, and the larvae therein 
were still alive ; application of water speedily brought the flies out. 
Dr. Marx mentioned another case~of retardation in Argiope basil- 
ica, the eggs of which, collected in 1882, did not hatch until four 
years afterwards. 
Mr. Howard then read a paper, of which he has prepared the 
following abstract : 
ON ENCYRTUS MONTINUS PACK. This Parasite was described by Packard 
* This is probably only a mutilated specimen of Hadrurus hirsutus. 
