INSECTS OF THE MOUNTAIN ASH. 539 



skin, thus presenting the form characteristic of the genus ; length, 2™™ to 3™™ (.08 to 12 

 inch) ; color grayish white with the first skin light gray and second skin usually 

 brown, sometimes dark graj'. 



Described from many isolated individuals occurring on smooth bark of a small 

 branch. On the rough bark of the trunk the scales are much more irregular in form, 

 and are so massed as to appear like a layer of dandruff. 



Female. — The body of ihe female is red, with the last segment light yellow ; this 

 segment presents the following characters : 



The anterior group of spinnerets consists of from eight to thirteen, usually ten ; the 

 anterior laterals are from twenty to thirty ; and the posterior laterals are from eight- 

 een to thirty-one. 



There are three pairs of Jobes. The median lobes are well developed ; the second 

 lobes are smaller, the third are still smaller, being sometimes obsolete ; the lobes of 

 the second and third pairs are deeply incised. There are conspicuous elongated pore* 

 upon the margin ; one laterad of each of the first, second, third, and fourth plates ; 

 one cephalad of the incision of third lobe ; and one midway between the third and 

 fourth plates. 



The spines upon the ventral surface are inconspicuous ; the first pair obsolete; the 

 second, third, and fourth pairs at or near the bases of the second, third, and fourth 

 plates. Those upon the dorsal surface are quite long ; the first spine of each side is 

 between the bases of the first lobe and the first plate ; the second and third spines 

 are upon the lateral lobule of the second and third lobes ; and the fourth spine is sit- 

 uated about two thirds distance from the third to the fourth plates. 



Eggs. — The eggs are purplish red. 



Scale of male. — The scale of the male is very small, being only .75™™ (.03 inch) In 

 length, narrow, usually straight and tricariuated ; larval skin brownish yellow, re- 

 mainder of scale snowy- white. 



Male. — Yellow marked with irregular reddish-brown spots ; thoracic band reddish 

 brown, sometimes darker than the other markings. Length of body including style, 

 .62™'" (.02 inch) ; length of style, .18™™ (.006 inch). On each side of the anterior part 

 of the thorax there is a black spot which resembles an eye. 



2. Dynastes grantii Horn. 



A beetle supposed by Dr. Horn to be this species has been found 

 by Mr. J. Doll to occur in September on the mountain ash in Colorado. 

 " They are always found near the tips of branches, where by means of 

 their projecting thoracic horn they scrape through the soft bark to 

 cause a flow of sap which is very sweet, and of this consists their food." 

 (Bull. Brooklyn Ent. Soc, vii, pp. 120, 151.) 



The following insects also occur on the mountain ash : 



3. Apatela occidentalis G. and R. 



4. Chrysobothris femorata Fabr. (Harris Correspondence, 311.) See 



also Bethune (Can. Ent., V, p. 140). 



5. Saperda bivittata Say. Apple-tree borer. 



6. An unknown lougicorn borer taken from a tree on Lake Kennebago, 



Maine, September 4, 1887. 



7. Mytilaspis pomicorticis Riley. 



