10 BULLETIN 889, U. S. DEPARTMENT OF AGRICULTURE. 
continuously observed under these conditions. Since the larve also, 
immediately after moltmg, consume the cast larval skin, it is impos- 
sible to find the remams of the molt by dissecting the stem. An 
attempt was made, therefore, to secure the number of molts and 
instars by splitting an alfalfa stem down the center, making an arti- 
ficial cavity in the split half, and fitting this tightly against the side 
of along glasstube. The larva was then placed therein and by these 
means a continual view of the larva was maintained, and thus in three 
cases records of molts and instars were obtained. Unfortunately, 
however, the data regarding the lengths of these instars are doubtless 
quite inaccurate, since the larve appeared to hurry their develop- 
ment and pass through to adults as quickly as possible. Apparently 
this was due to the fact that the larve were under unnatural condi- 
tions, such as being exposed to light and the glass. The three speci- 
mens reared were undersized, and an attempt at rearmg almost a 
hundred others met with failure. 
TABLE IV.— Molts and instars of the clover stem-borer (Languria mozardi) in alfalfa at 
Tempe, Ariz., 1916. 
Length of) Date of | Lengthof| Date of | Length of 
Cage No. Dake ee puso firstin- | second } second third third 
y star. molt. instar. molt. instar. 
Days. Days. Days. 
Leet oe oe aa ae eae toe Apr. 9] Apr. 14 5 | Apr. 17 Si eApEsa2 4 
Dae ne Basen os teats ees seloee d0s.4-|5-2d0s-2 = Dalsacd One ByqiR ns Glas se 4 
Se ee emmy cece ane cater wie uate dose o2l5 = GOse2 5Salea2dO errr Shi asedOee a= 4 
Total | Average 
Date of | Lengthof) pate of eng ive! length of 
Cage No. fourth | fourth ee 
pupation. larval | tempera- 
molt. instar. instar. stage. cares 
Ss ys Days. oF. 
1 ES A Aen oe len Ee Stop RET | eM E I ee a Apr. 26 5 | May 7 1 28 68 
DEI eee Sa) aes Re Oe pepo Setar em apes ae do 5 | May 10 14 31 69 
See e ee cd eae ee ee cee ee ee ese ae omens Apr. 27 6| May 8 11 29 69 
THE LARVAL HABITS. 
The larva, upon hatching, at first feeds within a quarter-inch 
cavity constructed by the adult before depositing the egg, but after 
a day or so begins to eat its way, first through the pith and later 
through both the pith and softer inner portions of the wall of the 
stem until it finally has a large cavity with only the thin hard exterior 
wall of the stem remaining. The larva gradually enlarges this tunnel, 
working its way both up and down the stem until often the entire 
length of the stem is traversed. The length of the tunnel usually is 
limited only by the length of the individual stem infested. Measure- 
ments of these tunnels show maximum lengths to be 30 inches. The 
larva is especially active and travels up and down the tunnel with a 
Pd 
