INSECTS OF THE MOUNTAIN ASH. 539 
skin, thus presenting the form characteristic of the genus ; length, 2 ram to 3 mm (.08 to 12 
inch) ; color grayish white with the first skin light gray and second skin usually 
brown, sometimes dark gray. 
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 the 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 lobes. 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 pores 
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 mm (.03 inch) in 
length, narrow, usually straight and tricarinated ; 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 mm (.02 inch) ; length of style, .18 mm (.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 occidentals G. and R. 
4. Chrysobothri8 femorata Fabr. (Harris Correspondence, 311.) See 
also Bethune (Can. Ent., V, p. 140). 
5. Saperda bivittata Say. Apple-tree borer. 
6. An unknown longicorn borer taken from a tree on Lake Kennebago, 
Maine, September 4, 1887. 
7. Mytilaspis pomicorticis Riley. 
