PEAR LYDA ; SOCIAL PEAR SAAVFLY. 139 



The web-nest, in which the caterpillars lay, was three 

 inches long, formed of threads spun from their mouths to the 

 Pear leaves on which they were feeding, and when received 

 (very likely a good deal injured in transit) was an irregular 

 piece of webbing about three-quarters of an inch less or more 

 in width. The earliest spun part, which was black with 

 decay and dirt of various kinds, was deserted, and the cater- 

 pillars lay for the most part in two clusters, one of about 

 twenty-two or more grubs, one of not so many. These were 

 closely packed together in their web, but reached out from it 

 to feed on the Pear leaves, which they greedily devoured, 

 starting at the edge, and made great havoc with. In one 

 instance they had eaten away about two-thirds of a leaf up 

 to the mid-rib, leaving only part of some of the chief side 

 veins. 



The spinning powers of the caterpillars were very noticeable 

 in endeavouring to reconstruct a shelter for themselves when 

 a Pear leaf, which had partly covered over a large party of 

 them, had been removed, 



A little later, on July 21st in the same year, a friend and 

 neighbour mentioned to me having observed a web-nest, 

 estimated at about three inches across, on a Pear tree in her 

 garden in Piomelands, St. Albans. This contained about fifty 

 shining, reddish orange, "worm-like" caterpillars, which were 

 doing so much damage that the nest had been cut off and 

 destroyed before I heard of it ; but from the description 

 (though without personal insiDection) I do not think it could 

 be other than one of the social collections of caterpillars of 

 Lyda pyri. 



The above are the only instances in which the attack has 

 been brought under my own notice ; but, looking at the bright 

 shiny orange colour of the many caterpillars feeding together 

 in a web several inches in diameter, and the devastation to 

 the spun-up leafage, the infestation is one calculated to attract 

 so much attention from the most unobservant, that it may be 

 conjectured if often present it would be much more enquired 

 about. 



The main points of the life-history as given by German 

 and English entomologists are as follows. The female sawfly 

 lays (towards the end of May) from forty to sixty eggs, mostly 

 on the under side of the Pear leaves. These eggs are longish 

 in shape, yellow, and look as if smeared with grease, and are 

 laid with great regularity in rows. The caterpillars, which 

 hatch out in a few days, are at first of a whitish yellow 

 colour, but become darker after the first moult, and begin 

 immediately to spin a loose web, in the threads of which they 

 climb to and fro. This web is enlarged, as requisite conse- 



