572 



PSYCHE. 



[December 1S93. 



under side of the leaves, producing a pustular 

 appearance on the upper side. 



History. This scale was discovered by 

 Hon. A. L. Christy in Las Cruces, and was 

 examined by Prof. C. H. T. Townsend, who 

 gave a short account of it as Aspidiotus n. 

 sp.?in Bull. 7, N. Mex. Exper. Station (1892) 

 p. 11. Prof. Townsend sent it to Prof. Corn- 

 stock, who said it was unknown to him, and 

 probably undescribed. On July 7, 1893, I 

 found it in abundance close to the railway 

 depot in Las Cruces, and after examining it, 

 came to the conclusion that it was a new- 

 species. Although I had seen A. ttvae in 

 Jamaica, it did not occur to me that it could 

 be that species, partly because Professor 

 Comstock did not recognize it, and partly 

 because the food-plant and habit were differ- 

 ent. However, I sent some to Professor 

 Riley, who remarked that the species came 

 nearest to A. uvae ; and that led me to com- 

 pare it with specimens of uvae from Ithaca, 

 N. Y., kindly sent by Mr. R. H. Pettit. The 

 result is that I cannot by any means distin- 

 guish it as a species from uvae, and even as 

 a variety it is not well marked, and would 

 hardly be separated but for the difference of 

 locality and food-plant. 



So far as observed, it is confined to Chilop- 

 sis ; and although grapes are extensively culti- 

 vated in and about Las Cruces, no case is 

 known of its attacking the vines. 

 , This adds another to the instances of 

 Coccidae differing in habit though hardly or 

 not at all in structure. They are what might 

 be termed physiological species, in contradis- 

 tinction to the ordinary or anatomical ones. 

 They suggest the idea that organisms present 

 differential characters of a class which we are 

 hardly beginning to understand. 



(2.) Mytilaspis alous, Cockerell, var. 

 concolor, n. v. 



$ scale elongate, narrow-mytiliform, 

 grayish-white. Exuviae pale straw color. 

 5 . Elongate pyriform, black or brown- 



black (dark brown by transmitted light), i£ 

 mm. long. Skin conspicuously striate (albus 

 also has the skin striate). Three pairs of 

 lobes; median lobes large and prominent, 

 rounded, notched without, rather widely 

 apart; 2nd lobes bifid, low, the caudad por- 

 tion largest; third lobes low, bifid, the two 

 parts about equal. A pair of spine-like plates 

 between the median lobes; and one such 

 plate beyond 2nd and 3rd lobes respectively. 

 A spine by the outer margin of each lobe. 

 Margin beyond the third lobe coarsely 

 crenate. Margin in region of 2nd and 3rd 

 lobes shows three or four sacs, elongated 

 with bulbous ends — no doubt glandular. 

 The anal orifice is at a considerable distance 

 from the caudal extremity. The ventral 

 glands are not in well-defined groups, but 

 scattered. On each side of the anal orifice, 

 slightly cephalad of it, is a group of about 8 

 orifices, not very close to each other; and 

 between this and the third lobe is another 

 scattered rather elongate group of about 8; 

 and a few other orifices are scattered here 

 and there, some single, others in little groups 

 of 3 or 4. 



Egg. The eggs (in caustic soda) are pe- 

 culiar for being of a dirty prussian-green 

 color. 



Larva. Elongate oval, eyes blue-black. 

 Last joint of antenna with two moderately 

 long hairs. Tarsal knobbed hairs long and 

 slender, with small knobs. Caudal filaments 

 ordinary, but some broken off. 



$ scale as usual in Mytilaspis. 



Parasite. Many $ scales show holes 

 where a parasite has escaped. 



Hub. Las Cruces, New Mexico; in great 

 numbers on a chenopodiaceous plant, on 

 which are also found Orthesia n. sp., larvae 

 of Lycaena exilis, and other interesting 

 things. It mostly infests the stems, but the 

 leaves show some scales, both on upper and 

 under sides. 



When I found this, I thought it must be 

 a new species, and it was surprising to find 



