43 



arranged transversely, while the twelfth or last segment is destitute of spines ; the 

 spines above mentioned hear several lateral and apical bristles, those at the apex 

 being somewhat over one-half as long as the spine itself; the spines are quite dusky, 

 except those lowest down on each side of the body, which are white; length, nearly 

 7 mm. 



When about to pupate the larva attaches itself by the hind end of its body to a 

 leaf or other object, and the old larval skin splits open from the head to the ninth 

 segment. 



Pitpa thinly covered with a light-yellow pubescence, light citron-yellow; head 

 nearly surrounded with blackish; first segment marked with two oblique black 

 spots on the dorsum, second segment marked with two similar but much larger spots, 

 third segment marked with two smaller black spots, fourth segment marked with 

 two dusky dots which are scarcely apparent ; fifth, sixth, seventh, and eighth seg- 

 ments each marked with two somewhat transverse black spots, those on the sixth 

 andseventh segments larger than any of the others ; wing-cases bordered above with 

 black ; length 5 mm. 



The other species of Orciis, namely, Orcus australasice, howevei, seems 

 to be doing better. Mr. Ooqnillett formed this impression some time 

 since, and further observations confirm its correctness. He finds it 

 difficult, as above stated, to rear 0. chalybeus in confinement, since the 

 larvse appear to attack only the recently hatched scale-insects. The 

 larvae of 0. australasiw, however, being larger and stronger than those 

 of the other species, tear off the hard shell of the Red Scale and feed 

 upon the insect itself. Moreover, it breeds more surely. From some 

 cause, climatic or otherwise, 0. chalybeus is unsuccessful in transforming 

 in the majority of cases. For instance, out of a cluster of five eggs of 

 chalybeus J attached to the upper side of an orange leaf at one of Mr. 

 Coquillett's breeding stations, only a single egg hatched, and out of 

 eight pupae collected at the same time, only two produced beetles. 



EXTRACTS FROM CORRESPONDENCE. 



On the Carbon Bisulphide Remedy against stored G-rain Pests. 



Allow me to add an important item in the method of keeping weevils and rats out 

 of a corn crib, by the use of the vapor of bisulphuret, or bisulphide, of carbon. 



The improvement I expect to make this year is to place on the floor of the bin an 

 oblong box made out of two 12-inch boards, the upper part coming to a sharp point. 

 The box is to he long enough to run two-thirds through the bin, boxed up at the 

 inner end to give it support. There is to be for a few feet from the inner upper 

 edge an opening cut out about half an inch Avide to give free vent for the vapor to 

 penetrate the corn. The necessity of this arrangement is, after the bisulphide has 

 disappeared by evaporation, to replace it with a fresh supply. This is to be done 

 in particular to keep out rats the year round. One good fumigation of the vapor is 

 sufficient to kill the weevils, hut it will take somewhat a continuation of the evap- 

 oration to keep out rats. 



As you are aware, the bisulphide of carbon is a highly volatile fluid, and the con- 

 tents in an open bottle will readily disappear by evaporation. To replenish the 

 fluid by the use of the long box, say every few months, would be all that is required, 

 and instead of using several bottles at once imbedded in the corn, I would use but 



