FAMILY HABITS IN BUTTERFLY LARV^S THE RURALIDS. 63 



plum, the excavation was found to reaeh quite across, and around the 

 pulpy stone, which, in the early larval stages, was not eaten, although, 

 after the third moult, it was devoured and the entire plum excavated ; 

 in no case was the skin eaten except in the autumn. Cook avers 

 (Can. Ent., xxxix., p. 232) that the larval habits, when feeding on 

 plum, do not differ essentially when Vaccinium vacillus is selected for 

 food ; in this case, when young, the larvae eat the floral organs, but, by 

 the time the second moult is reached, these have disappeared and the 

 green fruit is eaten. A tunnel just large enough to accommodate the head 

 is made in the side of a berry, and, as the mandibles work this deeper 

 and deeper, the "collar" is brought up flush with the surface of the 

 fruit, and this gives the larva the appearance of being halfway in a 

 berry not large enough to hold the half. Cook further notes that the 

 larvae apparently remain motionless for hours at a time, and do not 

 evince any desire to wander from a fruit-cluster till all the edible pulp 

 has disappeared ; he observed one larva take up a fixed position and 

 then clear out five berries in eight hours without moving. These 

 habits appear to be identical with those of Callophrys rubi on the 

 green berries of Rhammm catharticus and Cornus sanguined. Bethune 

 states" (Can. Ent., xxxvi., p. 1^6) that the larva of Incisalia irioides 

 was found in June, 1897, feeding in the same manner in young apples. 

 Of Incisalia nipJwn, Cook observes ((?a?z..i?n£.,xxxix.,p.259)that the young 

 larvaa feed on the tender tissues of the young needles of Finns rigida, 

 the larva boring a minute hole into which its head is thrust, in this 

 position excavating as much of the interior as it can reach without 

 getting its body inside. When first born, the larva is yellow- or grey- 

 green but soon becomes brown, marked with a creamy- white line on the 

 latero-dorsal ridge, the coloration being an excellent protection, whilst 

 the larva is feeding, on the brown needle-bundles ; when the needles 

 begin to thrust their tips beyond the sheath, the larva ascends to the 

 lowest visible green tissue, and bores into it in a manner which causes 

 the tip to droop away ; after the second moult the larva becomes green 

 with pronounced white stripes, and, coincident with this change, alters 

 its method of feeding, ascending to the tip of a young needle, which 

 it commences to devour, and then works gradually downwards, until it 

 encounters the brown sheath, when it attacks a fresh needle. This 

 appears to be very similar to the manner in which the larva of 

 Callophrys rubi is said to attack the young stems of Ledum palustre. 

 It is here, perhaps, advisable to note that Edwards mentions the 

 similarity in the larval feeding-habits of Incisalia henrici and Celastrina 

 pseudargiolus, since we ourselves have already drawn attention to the 

 similarity in these same habits in the parallel pair of Palaearctic species, 

 Callophrys rubi and Celastrina argiolus. Like the larva of Callophrys 

 rubi, the larvae of Incisalia niphon, etc., feed only in spring and early 

 summer, maturing rapidly from eggs laid in the first warm days of 

 March, April and May, pupating in the early summer, the pupal stage 

 lasting from June until the following spring. Thanks to Cook's energy 

 we now know tnat the larva of Incisalia polios feeds on Arctostaphylos uva- 

 ursi, although an account of the larval habits has not yet been published. 

 In their larval habits, the Thestorids appear to be not unlike the 

 Callophryids. The larvae are more specialised with regard to the food- 

 habit, being apparently confined to leguminous plants. Tbey have, 

 as in the Callophryids, a distinct spring-feeding habit, they also 



