42 [February, 



Hydropsycliid larva) without respiratory filaments, and the anal limbs 

 with their pencil of hairs are rather suggestive of the typical genus 

 Hydropsyche than of any other. The mandibles in the nymphs of 

 Titiodes are unique ; the only thing known to me at all analogous to 

 them occurs in the nymph of Odotifocerum aJMcorne : unfortunately, 

 in all nymphs which escape from their cases in the ordinary way, the 

 Blender hooked part is invariably broken off. These nymphs agi'eo 

 in their anal parts pretty closely with those of the Plectrocnemia- 

 Folycentropus group, but they differ from that group and agree with' 

 the Philopotamus-Wormaldia in having no respiratory filaments. 

 EXPLANATION OP FIGUEES. 



LAETiE. 



Fig. 1 — Left mandible from above {Tinodes aureola). 



„ 2— Eight „ 



„ 3 — Left „ „ below ,, „ 



„ 4— Eight „ „ „ „ „ 



„ 5-^Labium (maxillce and spinneret) from beneath {Tinodes aureola). 



,, 6 — Maxillse from above (Tinodes wmneri). 



„ 7 — Labrum ,, ,, ,, ,, 



NYMPH. 



„ 8 — Mandible from beneath {Tinodes aureola). 



These figures are all drawn with a Zeiss A objective. 

 Carluke, N.B. : October, 1889. 



OBSEEYATIONS ON COCCIDM (No. 6). 

 BY ALBERT C. F. MOEGAN, F.L.S. 



Genus DIASPIS. Costa. 



1. DlASPIS OSTRE^FOEMIS. 



Diaspis ostreceformis, Signoret, Ess. s. Coch., pp. 60, 121, 441, jjl. t, fig. 4 ; 

 ? Aspidiotus circularis, Fitch, 3rd Ann. Eep., 1856, p. 426 ; nee Aspidiotus ostrem- 

 formis, Curt., Gard. Chi'on., 1843, p. 805 ; nee Aspidiotus furfurus, Fitch, 3rd Ann. 

 Eep., 1856, p. 352 ; Coecus IIarrisii,'W&\bh, Prairie Farmer, May, 1860 ; Aspidiotus 

 Harrisii, Walsh, Eep. St. Ent., Illinois (1868), p. 53 ; Diaspis Rarrisii, Signoret, 

 Ess. s. Coch., p. 442 ; Cherines pyri, Boisduval, Ent. Ilort. (1867), p. 315 ; nee 

 Chermes pyri, Linne ; Diaspis ostreaformis, Comstock, 1st Ag. Eep., p. 311, pi. xv, 

 fig. 4, 2nd Eep. Corn. Exp. St., p. 94. 



This species was confounded with Aspidiotus ostreceformis, until 

 Mr. Douglas showed the differences (Ent. Mo. Mag., vol. xxiii, p. 239). 

 Prof. Comstock quotes Signoret as stating that the species is the same 

 as found by Fitch in New York, and described by him under the name 

 Aspidiotus circularis. But tSiguoret seems to have identified his 



