250 



BEITISH MOTHS. 



426. The Gray Dagger (Acronycta Psi). 



426. THE GRAY DAGGER. The antennae 

 are rather short, and are simple in both sexes ; 

 the fore wings are gray, with various black 

 linear markings : the principal of these are, 



first, an irregular cross, which bears some 

 small resemblance to a Greek psi placed side- 

 ways <-, and is situated near the anal angle : 

 exactly intermediate between this and the tip 

 of the wing, is a much smaller mark of. exactly 

 the same shape : the reniform and orbicular 

 spots are vague, but perceptible ; the orbicular 

 has a very delicate black border on its outer 

 side only, the reniform has a similar black 

 border on its inner side only, and this black 

 border is double at its lower extremity ; these 

 two semicircular markings are placed back to 

 back, and are connected by a short black line ; 

 together they constitute the second principal 

 black marking ; the third is a strong black 

 line which proceeds from the base of the wing 

 almost to its middle, and which emits three 

 or four lateral branches : the hind wings are 

 nearly white with darker wing-rays, and a 

 spotted fringe : the head, thorax, and body are 

 gray ; a black line originates in each palpus, 

 and passing along the head, includes the eye, 

 and along the thorax just above the base of 

 the wing. 



The head of the CATERPILLAR is rather wider 

 than the second segment ; the body is hairy 

 with parallel sides, but humped on the back ; 

 the first hump is slender, long, erect, horn- 

 like, and seated on the fifth segment ; the 

 second hump is shorter, broader, and on the 



- twelfth segment. The head is black, hairy, 

 and shining ; its divisions very convex ; the 

 second segment is black, with a very narrow 

 median yellow line ; the third, fourth, sixth, 



seventh, eighth, ninth, tenth, and eleventh 

 segments have a broad median yellow stripe, 

 and there is a median square spot of the same 

 colour on the hinder part of the twelfth seg- 

 ment; the horn-like hump on the fifth seg- 

 ment is intensely black, and clothed with 

 crowded short black hairs, intermixed with 

 scattered long ones; on each side of the 

 median stripe is an equally broad jet-black 

 stripe, and in this, on every segment, from 

 the fifth to the twelfth, both inclusive, are 

 two transverse bright red spots, with two 

 minute whitish warts between each pair, the 

 warts emitting black bristles : below the 

 black stripe, on each side, is a broad gray 

 stripe emitting gray hairs, and including the 

 black spiracles ; this gray stripe is reddish on 

 the anterior segments, the intensity of the red 

 increasing towards the head. The belly, legs, 

 and claspers are dingy flesh-coloured. It 

 feeds on whitethorn, pear, and a variety of 

 other trees, and is full-fed in September, 

 when it spins a whitish cocoon in the crevices 

 of the bark of trees, and therein changes to a 

 CHRYSALIS, in which state it remains through- 

 out the winter. 



The MOTH appears in June, and is common 

 everywhere. (The scientific name is Acro- 

 nycta Psi.} 



Obs. I am quite unable to distinguish by 

 words between this and the preceding species, 

 but am convinced they are distinct, from the 

 great difference of the caterpillar: in my 

 specimens, the reniform and orbicular spots 

 are more clearly defined in Psi than in 

 tridens ; they are very obscure and difficult 

 to trace in both, but Psi has most decidedly 

 the advantage in this respect. Mr. Double- 

 day, whose almost instinctive perception and 

 appreciation of difference is familiar to all 

 who know him, says that he finds little 

 difficulty in distinguishing the two insects 

 in their perfect state; but I am little for- 

 tunate, or, more properly speaking, less 

 gifted in the power of discrimination, and 

 never pronounce on either with feelings of 

 certainty. 



