PACKARD.! POTATO-INSECTS OF EUROPE. 735 



a dull-ocherons tiut, becoming darker as the period approaches of tLe 

 birth of the lly ; the antennie, eyes, wiugs, aud legs are visible beneath 

 their horny sheaths. At this period they are deprived of locomotion, 

 but the larviTi, although perfect maggots, aud destitute of feet, are able 

 to move along in moisture, at the same time waving about and thrust- 

 ing out their heads with great energy. There are thirty species of these 

 flies which inhabit England, and three or four of them have been bred 

 from putrid potatoes. One is called — 



" Sciara fucala Mei";. — When alive it is 1 line long. The male is of a pale inky black, 

 the head is small aud spherical, Avith two triarticulate feelers bent under, the two 

 horus are uot longer ihau the thorax, taueriug, pubesceut, inserted in front of the face, 

 aud sixtecu-jointed ; two basal joints the stoutest, the remainder obloug, apex conical ; 

 eyes lateral, kidney-shaped, and coarsely granulated ; ocelli three, but unequal ; trunk 

 gibbose, subquadrate, scooped out at the base, with two indistinct lines of short ochreous 

 hairs down tlie back ; scutel lunate, postscutel oval, of a grayish color ; abdouieu slen- 

 der, greenish-black, brownish after death, seven-jointed; the margins of the segments 

 pale, apex obtuse, aud furnished with two incurved biarticulate lobes ; two wings, in- 

 cumbent in repose, parallel, longer than the body, iridescent, slightly smoky, but 

 transparent aud clear at the base; nervures brown, excepting the central one, which 

 is scarcely visible, but forked and dark at the margin ; the costal uervure does uot 

 reach the base of the forked cell; balancers pale, dirty yellow or ochreous; six legs, 

 long, slender, and of a dirty-yellow or pale-olive tint. Female similar, but larger, being 

 li line long, the wings expanding nearly 3 lines, the thorax is not narrowed behind ; 

 the abdomen is spindle-shaped, attenuated, aud conical, terminating in two little par- 

 allel sheaths; the two balancers are dusky when dry. 



" This was bred in the winter of 1845-'46, and again in 1848, in vast quantities ; the 

 flies are also found throughout the summer in fields aud gardens, on umbellate flow- 

 ers and on grasses. I have likewise bred them from rotten turnips in March. 



"S. quinque-lineafa of Macqnart is 1^ line long. 'It is black, with five lines on the 

 thorax of a deep dull gray ; anterior hips testaceous; wings almost hyaline ;' balancers 

 brown or dirty white. 



" Specimens agreeing with this description were bred from rotten potatoes in March, 

 1848, and sent to me with the tubers containing the larvae and pupae also. The pota- 

 toes were like old rotten cheese, aud portions of the outside were covered with slimy 

 threads, which Mr. Graham saw the larvaj spin. He thinks they cause the 'scab' in 

 potatoes ; but I saw not the least vestige of the insect on one variety of my potatoes, 

 which was very scabby. 



^'S.pidicaria? Meigen, Hoff., is | a line long or upward, and is distinguished from 

 the two foregoing species by its longer antennie, which are equal in length to the rest 

 of the body. It is black, with testaceous legs ; the wings almost hyaline ; balancers 

 brown. 



"My specimens being as big again as Meigen's, with ochreous balancers, I am doubt- 

 ful if they be the S. pulcaria of that author. I bred them in August, 1845, from a rotten 

 potato. 



" Another dipterous insect was bred from the potatoes in less quantities. It also be- 

 longs to the family TiPULiDiE, and the genus Scalhojjse. It appears to be Meigen's. 



" S. punctata. — It is black and shining, the head is small, the eyes are kidney-shaped, 

 with three little ocelli on the crown ; the antenuic are short, stout, cjliudrical, aud 

 composed of eleven cup-shaped joints; thorax elongated and somewhat compressed, 

 with a white dot on each side ; scutel small and rough ; abdomen broad, oval, and de- 

 pressed ; wings ample, resting horizontally, transparent and iridescent, with a black, 

 costal, subcostal, and basal nervure, the lirst and second united beyond the middle, 

 aud divided near the base by an oblique nervure ; there are also four other very faint 

 longitudinal m.Tvuros,the apical one forked, the anal one waved; balancers yellowish ; 

 legs simple, longish, and rusty; extremity of thighs and shanks variegated with 

 fuscous ; feet brown, five-jointed, terminated by a pair of minute claws ; length, 1^ line ; 

 exijanse, 3^ lines. 



"The larvre from which these flies' proceed live in various putrid sub- 

 stances, and even in dung; they have also been bred from the cocoons 

 of silk-worms, in all probability containing decomposing caterpillars or 

 rotten pupa? ; they are from 2 lines to nearly ^ inch long, flat and 

 narrowed at both ends, of a dirty grayish-yellow color; the head is 

 brown and oval, with two short feelers ; the body is composed of twelve 

 pubescent segments, the first thoracic one with a prominent spiracle on 



