250 



BBITISH 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 sideways -, and is situated near 

 the anal angle : exactly intermediate be- 

 tween 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, hairv, and shining ; its divi- 



v * 



sions 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 segment ; 

 the horn-like hump on the fifth segment 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 throughout the winter. 



The MOTH appears in June, and is com- 

 mon everywhere. (The scientific name is 

 Acronycta 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 renif orm 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. 



