NATURAL SCIENCES OF PHILADELPHIA. 215 



tip of the wing and the diluted spots along the posterior margin are much 

 darker. 



Other differences, perhaps of less consequence, which I notice in my speci- 

 mens are : that the brown marks on the humeri are more distinct ; that the 

 brown spots on the pleura? are more numerous and darker ; that the base 

 and the tip of the halteres are pale, the whole intermediate portion being 

 dusky. 



Three specimens, (one tf and two 9) Washington, in May, (nob.) Upper 

 Wise, river (Mr. Kennicott,) Maine (Mr. Packard.) 



L. sol it aria. Thorax vitta media pallida, fusco-marginata, ahe fusco- 

 maculatse et nebulosae ; in area pobrachiali serie puuetorum fuscorum ; long. 

 'Jin. 4-5. 



Proboscis and palpi infuscated; front yellowish cinereous; vertex infus- 

 cated ; antennae fuscous, first joint yellow ; the two or throe following yellowish 

 at base, infuscated at tip. Thorax yellowish ; a brown stripe on the collare ; 

 a pale yellowish stripe, limited on both sides, by brown lines, on the praescu- 

 tnm ; two lateral brown stripes, abbreviated before and extended over the 

 turn behind ; scutellum and metathorax pale yellowish sericeous both with 

 lateral brown spots ; pleurae pale yellowish ; halteres with brown knobs ; 

 coxae pale ; femora tawny ; a pale rins* beyond the middle, followed by a 

 brown one near the tip ; tibiae and tarsi tawny, infuscated at their tips. Ab- 

 domen yellowish ferruginous ; an indistinct brown band, formed by a series 

 of spots in the middle of the tergum ; genitals pale; their structure like fig. 

 6. Wings yellowish with brown spots and clouds ; an oblique spot extends 

 from the posterior end of the stigma to the origin of the fork ; the margin of 

 the stigma is more or less infuscated ; a small brown ring is formed by this 

 margin on one side, and the clouded cross-veins at the tip of the subcostal vein 

 on the other ; origin of the petiole infuscated ; a series of more or less numer- 

 ous brown dots runs along the disc of the praebrachial area, the most conspicu- 

 ous among them being generally those opposite the origin of the petiole : an- 

 terior part of the pobrachial vein clouded ; discal cross-veins and great cross- 

 veins slightly clouded ; a pale brown band across the apical arere ; posterior 

 margin clouded, especially at the tip of the pobrachial and anal veins, and in 

 the subaxillary area. 



Two $ specimens ; Trenton Falls (nob. ) 



A (J' specimen from Maine seems to belong to the same species ; but it dif- 

 fers by having a spot and not, a ring at the tip of the subcostal vein ; the spot 

 at the origin of the petiole is larger and confluent with the corresponding dot 

 in the praebrachial area ; there are but two dots, instead of a series of dots, in 

 this area, near the base ; the last three segments of the abdomen are infus- 

 cated ; the pale ring on the femora is less distinct. 



N. B. Besides the differences mentioned in the descriptions of L. ci n c t i pe s, 

 immatura and solitaria, each of these species seems to have a constant 

 distinguishing character in the structure of the fork, formed by the mediasti- 

 nal cross-vein with the tip of the mediastinal vein. In L. immatura the 

 lower branch of this fork, (joining the subcostal vein.) is longer than the 

 upper one, and arcuated ; the upper one (joining the costal vein), is short, 

 straight, and perpendicular. 



The contrary is the' case in L. solitaria; here the upper branch is 

 longer and arcuated ; the lower being short, straight, and perpendicular. 

 In L. cinctipes both branches are about of the same length. The spe- 

 cimen of L. solitaria from Maine agrees in this respect with the typical 

 specimens. 



L. i n d i g en a. Flava, brunneo-vittata et marginata ; femora annulis duo- 

 bus fuscis ; alae fusco nebulosae ; long. lin. 4. 



Head black ; front with a silvery reflection ; antennae and palpi black. 



1859.] 



