Insects Injurious to the Mango. ii 
other fruits. The greatest damage usually is inflicted between the 
latter part of November and the ist of March. The abundance of 
the pest during this period depends chiefly on the existing climatic 
conditions. Unlike most other red spiders, the red spider of the 
mango and avocado confines its attacks to the upper surface of the 
foliage. 
NATURE OF INJURY. 
The foliage attacked turns brown and often drops prematurely, 
and at times there may be a heavy denudation as a result of the de- 
predations of these mites. They multiply so rapidly that the damage 
caused by them becomes quickly noticeable. The first indication of 
red spiders on the foliage is the pale spots scattered about over the 
leaf surface, showing the feeding places. As the feeding becomes 
more general most of the functional green matter in the leaf is de- 
stroyed, and in time such a leaf turns brown as if scorched and is of 
little use to the tree. Where the red spiders become numerous in a 
mango grove, considerable damage results from their attack on the 
hardened winter foliage through absorption of the functional leaf 
substance. It is the winter foliage which sustains the bloom in the 
spring and aids in the setting of the fruit. 
DESCRIPTION AND SEASONAL HISTORY. 
The egg.—The egg of the red spider is globose, smoky amber in 
color, about +45 inch in length, and bears a stalk which varies in de- 
velopment from a length equaling the height of the egg to a mere 
rudimentary papilla; guy fibrils are occasionally seen connecting the 
egg with the leaf. The eggs are laid on the upper surface of the leaf, 
usually along the midrib and lateral veins. The incubation period 
varies according to temperature and general climatic conditions. 
During midwinter, with mean daily temperatures between 60° and 
70° F., incubation requires from 7 to 11 days. During April and May 
incubation requires an average of only 4 to 5 days, with mean tem- 
peratures between 70° and 80° F. 
The larva.—The newly hatched larva is round and a very light 
yellow or almost colorless. It bears six legs and in size does not 
exceed that of the egg from which it emerged. The average period 
required for development of the larva is about 23 days. 
The nymphal stages.—Defore reaching the adult stage the mite 
goes through two molts. In the nymph stage which follows the larva 
stage, the mite attains an extra pair of legs, making four pairs. The 
first nymphal stage is about one one-hundredth inch in length and 
the second nymphal stage about one seventy-fifth inch. For the 
most part the habits of the first and second nymphal stages are similar 
