50 B.C. Entojiolocical Society. 



THE PREPARATORY STAGES OF DIACRISIA KASLOA, DYAR. 



r.v AimuR (JiiisoN. CHiEir Assistant ENTOiioi-OGisx, Division ok Entojioi.ogy. 



Ottawa. 



Ill I'.iOO we received at Ottinva specimens of a reddisli arctiiin wliicli we iilaced 

 under the name Antaietiu nifiihi, Bdv. Tliese were collected at Kaslo, B.C.. b.v 

 llr. J. W. Cockle. Two years later (1902) Mr. Cockle sent us eggs of the moth, and 

 notes were taken by me on the preparatory stages. In J9t>4 Dr. Dyar described the 

 moth as new and gave it the specific name kusloa;* one of the co-types was deposited 

 in the Division collection. In the same year the same author described the egg and 

 larval stages.f 



As the notes which I made on the iireparatory stages of the species are different 

 ill many respects from those published b.v Dr. Dyar. it seems advisable to present 

 them. They are as follows : — 



The eggs were received frnin Mr. Cockle on .June 19th. 10li2. probably laid on 

 June ]2tli; hatched .Tune 20th. 



Egy. — O.S mm. in diameter, 0.0 mm. high, shaped like that of TIn/mcUciis wtnu. 

 Scud.; semi-ovoid: at first pale creamy, changing to a dirty white before hatching; 

 seta» plainly visible at this time; shining, smooth, except under a microscope, when 

 the surface appears slightly roughened. 



Larval Stage I. — Length at first 2.2 mm., colour white, the tubercles giving tlie 

 body tlie appearance of being striped traiisversel.v witli black lines. After feeding 

 the larv;e are pale green, the skin sliiuiug. Head OA mm. wide, pale brown, ocelli 

 black. Thoracic shield concolorous with head, paler in centre, S-haired. Tubercles 

 greyish-black, shining, i small, ii large and rounded, iii and iv smaller than ii and 

 elongate, about same size, v sliglitly smaller than iv. Tubercle iii, 2-haired, others 

 single. Seta= long and slender. Between tubercles ii and iii and iv and v a series 

 of reddish-brown blotches are iiresent. Spiracles minute, black. Thoracic feet 

 slightly darker than venter ; prolegs smoky exteriorly. 



Tlie young larvie were given sorrel, dock, dandelion, lainb's-quarters, timotliy, 

 and lupin, and fed on all of tliese. 



Stage 11. — Length 4 mm. Head O.G mm. wide, in some specimens wholly pale 

 brown, others jiale brown with .a smoky patch near vertex of clypeus. Body pale 

 green. The whole skin is now more or less splashed with crimson, quite intense in 

 some specimens, the larger blotches in a line with tubercle ii. Tubercles black, 

 shining, the dorsal series bearing mostly black bristles, and the lower lateral series 

 silvery bristles. A very faint whitish dorsal stripe is present, dividing tlie thoracic 

 shield, which is reddish in some larvfe and black in others. Feet all concolorous 

 with venter, but bearing blackisli plates. 



Stage III, — Length C..5 mm. Blackisli larva-, having a pale-brownish head, a 

 pale-blue dorsal stripe, and bearing slender blackish bristles. Head 1 mm. wide. 

 After one day's feeding the larvm lose their blackish colour ; under a lens the skin 

 aiipears green, and the whole body is splashed and marked as before, but the blotches 

 are not now so intense in colour, being more of a dark brownish-red, the larger 

 blotches being near tubercle ii, as previously. Tubercles black, shining, i about one- 

 fifth the size of ii, iii as long but not so wide as ii, iv and v smaller than iii. 

 Spiracles very small, black, and immediately above the auterior edge of tubercle iv. 

 Bristles as before, faintly barbed. Thoracic shield blackish. Thoracic feet con- 

 colorous with venter semi-translucent, bearing dark iilates; prolegs dark smoky. 



Stage lY. — Length 11 mm. Head 1.4 to l.i! ram. wide; yellowish-brown, or 

 yellowish-brown with a large dark-brown patch near apex of elypeu.s. Blackish 

 larva with black bristles on dorsum and upper portion of sides, and yellowisli or 

 rust-red bristles along the lower portion of sides. Dorsal stripe yellowi.sh. in some 

 specimens faint. The ground colour of the skin is greyish-green, but the whole body 



* Proceedings of Entomological Societ.v of Washington. ■\'I.. p. 18, .Tauuni-y. ltJ04. 



t rroceedings o£ Entomological Sociot.v of Unit.'d States National .Mns.'um, X.WII.. ii. Tftl. 



