PRACTICAL ENTOMOLOGY. 431 



With spring there seems to come new life and vigor to the lice. If we may 

 judge from the rapid growth in April and May, and also from the hundreds 

 of eggs which each louse produces, we must conclude that at this time the lice 

 are serious pests, doing no inconsiderable injury to the trees; especially when 

 there are hundreds and thousands of them, so thick indeed that they overlap 

 each other like shingles on a roof, as is often the case, especially with the 

 maple bark louse. 



At this time, the lice secrete a copious shower of nectar — tlie so called 

 " honey dew" — which so thickly coats the upper surface of the leaves of the 

 trees that they appear as if varnished. This unctuous sweet also falls to the 

 ground and coats the grass and stains the sidewalks. This nectar attracts 

 bees, wasps, flies, and other sweet-loving insects. This is especially enticing 

 to the bees at such times as they can not gather from flowers, and enables 

 them to fill their hives between the fruit bloom and the white clover. This 

 secretion of such a large amount of sweet must be quite a serious drain on the 

 vital energies of the scale lice, and as we believe that no such physiological 

 activity is purposeless, it is interesting to cast about for the compensation 

 which the bark lice receive for this bounteous gift of sweet. From what has 

 already been said, we see that the lice early become stationary, and so there is 

 very little time that they can scatter from tree to tree, and, indeed, at this 

 early date these wee insects move only by use of their small legs, and so 

 could hardly get, unaided, from one ti'ee to another. Just, however, as the 

 minute lice are rapidly running from twig to leaf, the bees and other insects 

 are lapping up the nectar, and many of the wee lice will run upon them, 

 and so the bees will become the agents to distribute the lice to other trees. 

 It is more than likely too that the presence of the bees and wasps keeps 

 predacious insects away which might otherwise prey upon the lice. We shall 

 see in the sequel that even these little lice do serve as food for other insects. 

 We see then that the nectar is of vast indirect service to the lice; it aids in 

 colonization, and attracts sentinels which serve to protect the lice. 



THE MALES. 



Some of the scales as seen on the leaves in July — as shown by Miss Emily 

 Smith in the case of the maple bark louse — American Naturalist, vol. 12, 

 p. 655 — become, narrower, lighter colored, and more convex than the others. 

 These are to produce males. IMie males come forth in August. They have 

 (Fig. 10) two wings and fly about the trees with great rapidity, and are not 

 found after early September. Coition then takes place, when the males die, 

 while the females continue to sip, grow, and destroy, and do not deposit their 

 eggs till the following May. Tlie males have well developed antennas which 

 are ten jointed and hairy. The abdomen terminates in a tubercle, beside 

 which are seen the longer setas. 



REMEDIES. 



It has often been noticed that these bark lice after being very common, 

 will suddenly disappear, even though no effort is made on our part to destroy 

 them. This riddance is doubtless owing to the agency of several insects 

 which destroy the scale lice and their eggs. Mr. C. M. Weed and myself have 

 discovered several insect enemies preying upon these scale lice, some of which 

 seem to have been previously unnoticed. An undescribed chalcid parasite of 

 the genus Encrytus was reared from the species of Lecanium on the red ash 

 i^Fraxinus 2)uhescens) . Only one specimen of this was taken. 



